Catalyst for cleaning exhaust gases, method of regenerating said catalyst, as well as device and method of cleaning exhaust gases using said catalyst

FIELD: chemistry.

SUBSTANCE: invention relates to a catalyst for cleaning exhaust gases, a method of regenerating such a catalyst, as well as a device and a method of cleaning exhaust gases using the said catalyst. The invention describes a catalyst for cleaning exhaust gases where a noble metal is attached to a metal oxide support. In an oxidative atmosphere, the noble metal on the surface of the support is in a high oxidation state and the noble metal is bonded to the cation of the support though an oxygen atom on the surface of the support with formation of a surface oxide layer. In a reductive atmosphere, the noble metal on the surface of the support is metallic state and the amount of noble metal open on the surface of the support, measured through CO chemisorption, is equal to or greater than 10 at % of the total amount of noble metal attached to the support. Described is a method of regenerating a catalyst for cleaning exhaust gases in which the above described catalyst for cleaning exhaust gases undergoes oxidative treatment by heating in an oxidative atmosphere which contains oxygen, and reduction treatment. Described also are devices for cleaning exhaust gases (versions) and a method of cleaning exhaust gases, involving cleaning exhaust gases by bringing the exhaust gases into contact with the above described catalyst.

EFFECT: prevention of reduction of catalyst activity.

18 cl, 11 tbl, 46 ex, 10 dwg

 

The technical field

This invention relates to a catalyst for purification of exhaust gases, the method of regeneration of such catalysts, as well as to a device and method for purification of exhaust gases by using this catalyst.

The prior art prior to this invention

The catalysts for purification of exhaust gases typically used for removing harmful components such as gaseous hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx), in the exhaust gases of automobile engines. As such catalysts for purification of exhaust gases of known three-component catalysts, which simultaneously purify the exhaust gases formed by combustion with theoretical ratio of air-fuel, HC, CO and NOxand typically includes a substrate (supporting substrate)made of cordierite, metal foil or the like and formed into a honeycomb structure; the media (layer, the pinned catalyst), made of active alumina powder, powder of silicon dioxide or the like and formed on the substrate surface; and a component of the catalyst of a noble metal such as platinum, mounted on the carrier.

For example, publication of unexamined patent application of Japan No. Heisei 5-317652 (Document 1) discloses a catalyst for isdi exhaust gases, manufactured by application of the oxide of the alkali earth metal and platinum on a carrier formed of a porous material. In addition, publication of unexamined patent application of Japan No. Heisei 6-99069 (Document 2) discloses a catalyst for purification of exhaust gases containing a carrier substrate and a layer component of the catalyst, manufactured by fixing on the surface of the carrier substrate of the catalyst components comprising from 1 g to 20 palladium, from 50 g to 250 g of aluminum oxide, from 10 g to 150 g of cerium oxide and from 8 g to 50 g of barium oxide per liter of the volume of the reference framework. In addition, publication of unexamined patent application of Japan No. Heisei 10-174866 (Document 3) discloses a catalyst for purification of exhaust gases containing layer of the first catalyst formed by attaching at least palladium on the first porous medium and the layer of the second catalyst, is formed on the surface layer of the first catalyst fastening at least rhodium on the second porous medium, in which the weight of palladium, enshrined in the first layer of catalyst per unit mass of the first porous carrier, than the mass of the rhodium contained in the second layer of catalyst per unit mass of the second porous medium.

However, when the catalysts for purification of exhaust gases, as described in Documents 1 to 3 are the hcpa is setiu exhaust gases at high temperature (especially 800°C or higher), the problem with loss of catalytic activity, which is due to the fact that the particles of the noble metal having a catalytic activity such as platinum, rhodium or palladium fixed on the carrier, are aggregated and then are sintered (the growth of the particles), resulting in the reduction of their specific surface area.

In addition, publication of unexamined patent application of Japan No. 2004-41866 (Document 4) discloses a catalyst for purification of exhaust gases containing complex oxides with perovskite structure specific formula, the complex oxide includes at least one element selected from rare earth elements, which certainly contains a rare earth element and contains no rare earth element, which can have a valence less than 3; at least one element selected from A1 and transition elements excluding cobalt, palladium and rare earth elements; and palladium. However, in the catalyst for purification of exhaust gases, as described in Document 4, a noble metal forms a solid solution in the perovskite structure and is stable oxidation state, and this raises the issue that hampered the functioning of the noble metal contained in the structure, as the active sites of the catalyst, so catalyti is a mini activity is not high enough.

In addition, publication of unexamined patent application of Japan No. 2003-220336 (Document 5) discloses a catalyst for purifying exhaust gases, comprising a carrier, which contains cerium oxide and a metal catalyst comprising a transition metal and a noble metal and is fixed at least on the cerium oxide in the catalyst, the ratio between the atomic ratio of the transition metal and cerium and the atomic ratio of the transition metal and the noble metal is in a given interval. However, the catalyst for purification of exhaust gases, as described in Document 5, not perfect enough to restore its catalytic activity by re-dispersion of the noble metal by the process of regeneration.

In addition, publication of unexamined patent application of Japan No. 2005-270882 (Document 6) discloses a catalyst made by fixing one kind or two or more kinds of particles of metal catalyst comprising one kind or two kinds or more transition metals or oxides of transition metals with an atomic number of from 10 to 50,000 on a porous carrier comprising the oxide of one kind or two or more kinds of oxides of cerium, cerium-zirconium, cerium-zirconium-yttrium and cerium-lanthanum-zirconium. In addition, publication pending bid, medium, small is on the Japan patent No. 2002-79053 (Document 7) discloses a catalyst for purification of exhaust gases, made application to fire a three-dimensional structure of the coating of the catalytic active component containing a composition of zirconium oxide, which contains the noble metal is at least one species, the fire-resistant inorganic oxide, cerium and lanthanum and has a monolithic structure of zirconium oxide having a tetragonal crystallographic structure. Further, publication of unexamined patent application of Japan No. 2004-141833 (Document 8) discloses a catalyst for purifying exhaust gases in which a noble metal attached to the particles of the metal oxide containing cerium oxide and zirconium dioxide, and the particles of metal oxide have a Central part containing more cerium oxide than that of Zirconia, and the surface layer containing more zirconium dioxide than cerium oxide. In addition, publication of unexamined patent application of Japan No. 2004-243177 (Document 9) discloses a catalyst for purifying exhaust gases in which a noble metal attached to the particles of complex oxide containing at least CeO2and ZrO2in each particle that satisfies the ratio of 0.5≤CZr/CCe≤1.5 a, if CCeis the content in % by weight of CeO2powder complex oxide, CZris the content in % by weight ZrO2 powder complex oxide, and in which a noble metal is fixed on the powder particles of complex oxide using a water solution of a salt of a noble metal, with pH less than the pH of the suspension formed by immersion of the powder of the complex oxide in pure water.

However, in the catalyst, described in Document 6, due to the fact that the noble metal is fixed in the form of clusters, in order to try to provide thermal stabilization of the particles of the noble metal, there is the problem consists in the fact that, if you are using a noble metal resistant to high temperatures, the catalytic activity per unit amount of the noble metal decreases. In addition, in the catalyst for purification of exhaust gases, as described in Document 7, the fixing of the noble metal is insufficient, resulting in the problem associated with the growth of grains of the precious metal and the loss of catalytic activity. Moreover, since the catalysts for purification of exhaust gases, as described in Documents 8 and 9, have uneven content of cerium and zirconium particles inside the media, their resistance is low, and therefore they have insufficient resistance to growth of particles of the noble metal. Moreover, in the catalysts for purification of exhaust gases, described what's in the Documents 6 to 9, catalytic activity on a unit amount of the noble metal after use over a long period of time is not high enough, and sufficient catalytic activity is not restored through the process of regeneration.

On the other hand, to resolve problems with loss of catalytic activity due to sintering, as described above, there are various methods of regeneration of the catalysts for purification of exhaust gases, in which the growth of the grains in the particles of the noble metal. For example, publication of unexamined patent application of Japan No. Heisei 7-75737 (Document 10) discloses a method for regenerating catalyst for purification of exhaust gases produced by fixing the precious metal as an active component in the inorganic porous matrix, which includes the effect of halogen on the catalyst to form a halide of a noble metal on this matrix, with subsequent removal of the halogen of the halide. However, in the method for regenerating catalyst for purification of exhaust gases, in which the halogen effect on the catalyst, as described in the Document 10, the regeneration of the catalyst is extremely difficult in a state in which the catalyst installed in the exhaust system of the internal combustion engine, and is the limit with what the treatment time, required for the regeneration process by re-dispersion of the noble metal with the increased grain size, to restore catalytic activity.

In addition, publication of unexamined patent application of Japan No. 2000-202309 (Document 11) discloses a method in which a catalyst for purifying exhaust gases, comprising a medium which contains at least one component selected from the oxides of alkaline earth metals and rare-earth metal oxides, and platinum mounted on the carrier, is subjected to oxidation processing, after which the catalyst is subjected to recovery processing. However, even the method described in the Document 11 is unsatisfactory from the viewpoint of shortening the time and lowering the temperature required for regeneration by re-dispersion of platinum particles with increasing grain size, to restore catalytic activity.

Description of the invention

This invention was made considering the above problems of the conventional technologies. The purpose of this invention is the provision of a catalyst for cleaning exhaust gas, which is enough to hold back the aggregation of particles of the noble metal to substantially prevent ro is t grains of precious metal, even if it is exposed to exhaust gases at a high temperature for a long period of time, whereby the catalyst enables a sufficient deterrent reduction of catalytic activity and the possibility of re-dispersion of the particles of the noble metal in a short time, so a simple way to restore catalytic activity, when grain growth using a catalyst, even if the particles of the noble metal are in an area with a relatively low temperature, and also allows regeneration of the catalyst is simple, even in a state in which it is installed in the exhaust system of the internal combustion engine, the provision of a method of regeneration of this catalyst for purification of exhaust gases, and also the device for purifying exhaust gas and method for purification of exhaust gases by using this catalyst for purification of exhaust gases.

The authors of this invention have conducted careful studies to achieve the above goals. As a result, the authors found that the grain growth of the noble metal can significantly hold back for a long period of time using a specific catalyst having a surface oxide layer formed over the an Association of the noble metal cation media through the oxygen atom on the surface of the carrier, to ensure sufficient deterrence reduction of catalytic activity. In addition, they found that the catalyst can be effectively regenerated by the fact that the catalyst for purification of exhaust gases is subjected to oxidizing and reducing treatments, even if the catalyst is used for a long period of time, and grain growth of the noble metal, extending this aspect of the invention.

The catalyst for purification of exhaust gases according to this invention is a catalyst for purification of exhaust gases, in which a noble metal is fixed on the carrier oxide of the metal, while

in an oxidizing atmosphere the precious metal is on the surface of the medium in a condition of high degree of oxidation, and this noble metal is associated with the cation of the media via an oxygen atom on the surface of the carrier, to form a surface oxide layer, and

in a reducing atmosphere, a noble metal is on the surface of the carrier in the metallic state, and the amount of noble metal, open at the surface of the carrier measured by CO chemisorption, is 10 at.% or more of the total amount of the noble metal attached to the media.

In the catalyst for purification of exhaust gases according to this the invention of the noble metal is preferably at least one element, selected from the group consisting of platinum, palladium and rhodium.

In addition, in the catalyst for purification of exhaust gases according to this invention the value of the binding energy of the 1s orbitals of the oxygen atom in the carrier is preferably 531 eV or less.

In addition, in the catalyst for purification of exhaust gases according to this invention, the electronegativity of at least one cation among cations in the media preferably less electronegativity of Zirconia.

Moreover, in the catalyst for purification of exhaust gases according to this invention it is preferable that the molar ratio of the cation and the noble metal (cation/noble metal) was 1.5 or more, the cation was opened on the surface of the carrier and had an electronegativity less electronegativity of Zirconia.

In addition, in the catalyst for purification of exhaust gases according to this invention, the carrier preferably contains a complex oxide of Zirconia and/or alumina and at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, more preferably contains a complex oxide of Zirconia and/or alumina and at least one element selected from the group consisting of magnesium, calcium, barium, l is ntana, cerium, neodymium, praseodymium, yttrium and scandium.

In addition, it is not known exactly why this goal is achieved by a catalyst for purifying exhaust gases according to this invention, however, the authors of the present invention suggest the following. Namely, in the catalyst for purification of exhaust gases according to this invention the metal oxide carrier (preferably the medium in which the electronegativity of the cation in the metal oxide carrier is less than the electronegativity of zirconium and the magnitude of the binding energy of the 1s orbitals of the oxygen atom in the metal oxide carrier is 531 eV or less) is extremely strong interaction with the noble metal. In addition, in the catalyst for purification of exhaust gases according to this invention, including the media, in an oxidizing atmosphere formed surface oxide layer, as shown in figure 1, in which the noble metal is associated with the cation of the media via an oxygen atom on the surface of the carrier. In addition, in the catalyst for purification of exhaust gases according to this invention, is formed as such a surface oxide layer, grain growth of the noble metal can significantly hold back, even if the catalyst is exposed to exhaust gases at a high temperature for a long lane is an ode to time. In addition, in the catalyst for purification of exhaust gases according to this invention in a reducing atmosphere, a noble metal goes into the metallic state on the surface of the carrier, and the amount of noble metal, open at the surface of the carrier, which is measured by CO chemisorption, is 10 at.% or more of the total amount of the noble metal attached to the carrier, and thus the noble metal that serves as the active sites of catalyst stably present on the surface of the carrier in a highly dispersed state (in a state of high dispersion in the form of fine particles), which provides a consolidation of high catalytic activity.

In addition, even if the catalyst for purification of exhaust gases according to this invention is used for a long period of time for which the growth of the grains, precious metal exhibits a strong interaction at the interface with the carrier, thus forming a surface oxide layer by heating the catalyst in an oxidizing atmosphere containing oxygen, preferably by heating at a temperature from 500°C to 1000°C) and the gradual dispersion with the transition to a dispersed state on the surface of the carrier. As a result, the noble metal on the carrier is visokog sergiovanni and fixed in the state of oxide through oxidation treatment for a relatively short period of time (re-dispersion). Then the noble metal in the state of oxide is restored to the metallic state rehabilitation treatment, whereby it returns to its catalytic activity.

The catalyst for purification of exhaust gases according to this invention preferably satisfies the Condition (I)below.

<Condition (I)>

The catalyst also includes an additional component attached to the carrier and containing at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, the number of noble metal attached to the carrier is in the range from 0.05% to 2% by weight of the weight of the catalyst, and the molar ratio (the number of additional component/amount of precious metal) the amount of additional component attached to the carrier, and the amount of noble metal is in the range from 0.5 to 20 per metal.

When the catalyst for purification of exhaust gases according to this invention satisfies the Condition (I), an optional component preferably contains at least one element selected from the group consisting of magnesium, calcium, neodymium, praseodymium, barium, lanthanum, cerium, yttrium and scandium.

In addition, in this case, the catalyst for PTS the strict exhaust gas preferably contains iron, mounted on the carrier, with the molar ratio (the amount of iron/number of precious metal) amounts of iron, fixed to the carrier, and the amount of the noble metal is in the range from 0.8 to 12 per metal.

The authors of the present invention found that, when the catalyst for purification of exhaust gases according to this invention satisfies the Condition (I), grain growth of the noble metal may be substantially restrained for a long period of time, whereby a sufficiently constrained by the loss of catalytic activity, and also found that the use of oxidizing and reducing treatments to such a catalyst for purification of exhaust gases can reduce the time required for the regeneration process, and to reduce its temperature, resulting in efficient recovery of catalytic activity.

In addition, in this case, the reason why the above-mentioned purpose is achieved, it is not clear, but the authors of the present invention suggest the following. Namely, in the catalyst for purification of exhaust gases, satisfying the Condition (I), a complex oxide (preferably a complex oxide in which the value of the binding energy of the 1s orbitals of oxygen is 531 eV or less, and the electron density on the oxygen atoms is high) Zirconia and/or alumina and at least one element, selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, shows an extremely strong interaction with the noble metal. Also, since the carrier is secured additional material, is formed by turning at least one additional element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, the basicity of the medium increases and, as a result, the carrier exhibits a stronger interaction with the noble metal. Therefore, in the catalyst for purification of exhaust gases, satisfying the Condition (I), even if it is exposed to exhaust gases at a high temperature for a long period of time, grain growth of the noble metal particles can be restrained to a greater degree, resulting in additional deterrence reduction of catalytic activity.

In addition, when the catalyst for purification of exhaust gases, satisfying the Condition (I)is used for a long period of time, causing grain growth, a strong interaction occurs on the boundary surface between the particles of the noble metal, is fixed in a state with a larger grain size, and media. As a consequence, the heat to which telesfora in an oxidizing atmosphere, containing oxygen, preferably heated at a temperature from 500°C to 1000°C) enforce the noble metal to the formation of complex oxide and a metal oxide together with the carrier, so that the noble metal is gradually dispersed in a distributed on the surface of the carrier state. In the result, the noble metal on the carrier becomes highly dispersed and enters a state of oxide fixed on the media, when carrying out the oxidation treatment (re-dispersion) within a relatively short period of time, after which a noble metal in a state of oxide is restored to the metallic state rehabilitation treatment, whereby it returns to its catalytic activity.

In addition, the catalyst for purification of exhaust gases according to this invention more preferably satisfies the Condition (II), below.

<Condition (II)>

The catalyst also contains iron, fixed to the carrier, and the amount of noble metal attached to the carrier is in the range from 0.05% to 2% by weight of the weight of the catalyst, and the molar ratio (the amount of iron/number of precious metal) amounts of iron, fixed to the carrier, and the amount of the noble metal is in the range from 0.8 is about 12 per metal.

The authors of the present invention found that, when the catalyst for purification of exhaust gases according to this invention satisfies the Condition (II), grain growth of the noble metal may be substantially restrained for a long period of time, along with significant restraint reduction of catalytic activity, and found that this catalyst can be effectively regenerated by applying oxidizing and reducing treatments to such a catalyst for purification of exhaust gases.

In addition, in this case, the reason why the above-mentioned purpose is achieved, it is not clear, but the authors of the present invention suggest the following. Namely, in the catalyst for purification of exhaust gases, satisfying the Condition (II), complex oxide (preferably a complex oxide in which the value of the binding energy of the 1s orbitals of oxygen is 531 eV or less and the electron density on the oxygen atoms of the high Zirconia and/or alumina and at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, shows an extremely strong interaction with the noble metal. In addition, iron (II) is attached to the carrier containing the complex oxide. To t the th same is iron forms an alloy with the noble metal in a reducing atmosphere and is deposited on the surface and around the noble metal oxide in an oxidizing atmosphere. For this reason, the consolidation of Fe in the medium makes it possible to further restrain grain growth of the noble metal in different atmosphere using a catalyst, providing the opportunity for more adequate deterrence deterioration of catalytic activity. In addition, in such a catalyst for purification of exhaust gases, due to the fact that Fe is close to the noble metal, facilitated the oxidation and reduction of the noble metal and accordingly there is the possibility of increasing the activity of the reaction exhaust gases. In particular, the addition of Fe improves the ability to recover. In addition, when the catalyst is regenerated by this method of regeneration in the case where the catalyst for purification of exhaust gases, satisfying the Condition (II)is used for a long period of time, which results in grain growth of the noble metal particle diameter of the noble metal attached to the carrier, can be reduced and thereby the catalytic activity can be restored easily enough.

In addition, the catalyst for purification of exhaust gases according to this invention more preferably satisfies the Condition (III)below.

<Condition (III)>

p> The carrier is a carrier having a fluorite structure and containing a complex oxide of zirconium and at least one metal element comprising cerium, and selected from the group consisting of rare earth elements and alkaline earth elements; the number of the metal element contained in the carrier is in the range from 51 mol.% up to 75 mol.% in the calculation of the metal in relation to the number of the carrier; the number of cerium contained among other metal elements is 90 mol.% or more per the total amount of metal elements; and the amount of noble metal, mounted on 100 g of the carrier, two times or less larger than the standard value X is in the range of from 0.01 g to 0.8 g, with a standard value X is calculated according to equation (1):

X=(σ/100)·S/S·N·Mnm·100 (1)

where X is a standard value (unit: g) of the amount of precious metal to 100 g of the carrier; and σ represents the probability (unit: %), with which the metallic element is surrounded by a metal element, the probability of σ is calculated in accordance with equation (2):

σ=M-50 (2)

where M represents the share (unit: mol. %) of the metal element contained in the media; S is the specific surface is t (unit: m 2/g) media; s represents a single area (unit: Å2/number one cation, this single area s is calculated by the equation (3):

[Formula 1]

s={a2+(√2)·a2+(√3/2)·a2}/3·2 (3)

where a represents the lattice constant (unit: Å); N is the Avogadro's number (of 6.02·1023(unit: number); and Mnmrepresents an atomic mass of noble metal attached to the media.

The authors of the present invention found that, when the catalyst for purification of exhaust gases according to this invention satisfies the Condition (III), grain growth of the noble metal can significantly hold back, even if the catalyst is exposed to exhaust gases at a high temperature for a long period of time, by providing more adequate deterrence reduction of catalytic activity, and also found that the catalytic activity can be easily recovered by re-dispersion of the noble metal, even when the growth of grains that catalytic activity at a single fixed number of precious metal can be quite high, and that the catalyst may be excellent catalytic activity.

Cu is IU, in this case, the reason why the above-mentioned purpose is achieved, is not precisely known, but the authors of the present invention suggest the following. Namely, in the catalyst for purification of exhaust gases, satisfying the Condition (III), complex oxides of zirconium and at least one element selected from the group consisting of rare earth elements and alkaline earth elements including cerium, shows extremely strong interaction with the noble metal. This is due to the binding of the noble metal with cerium (Ce) or rare earth element and alkaline earth metal via an oxygen in an oxidizing atmosphere. Therefore, grain growth of the noble metal can significantly hold back, even if the catalyst is exposed to exhaust gases at a high temperature for a long period of time, whereby a sufficiently restrains the deterioration of catalytic activity.

In addition, in the catalyst for purification of exhaust gases, satisfying the Condition (III), the carrier has the structure of fluorite, and the proportion of cerium metal element is in the range specified above, therefore, a decrease in specific surface area significantly constrained even in an atmosphere with high temperature, since the cerium is in the media in the form of solid solution and the number of seats capable of attaching a noble metal, on the number of media is greatly increased; in accordance with this grain growth of the noble metal is fairly limited and is provided with the ability to curb the deterioration of catalytic activity. Moreover, since the amount of the noble metal is in the range that meets the above conditions, constrained the growth of grains attributable to an excessive amount of precious metal.

Moreover, when the catalyst for purification of exhaust gases, satisfying the Condition (III)is used for a long period of time, which results in the growth of grains, heating the catalyst in an oxidizing atmosphere containing oxygen (preferably heated at a temperature from 500°C to 1000°C), causes the noble metal to the formation of complex oxide and a metal oxide together with the carrier, so that the noble metal is gradually dispersed in a distributed on the surface of the carrier state. In the result, the noble metal on the carrier becomes highly dispersed and enters a state of oxide fixed on the media, when carrying out the oxidation treatment (re-dispersion), then the noble metal in the state of oxide is restored to the metallic state restore the nutrient processing, whereby it returns to its catalytic activity.

Method for regenerating catalyst for purification of exhaust gases according to this invention is a method of applying oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and a restoration processing to the catalyst for purification of exhaust gases according to this invention.

In the method for regenerating catalyst for purification of exhaust gases according to this invention (i) the temperature when the oxidation treatment is preferably from 500°C to 1000°C, and/or (ii) the concentration of oxygen in the oxidizing atmosphere is preferably 1% by volume or more.

In addition, in the method for regenerating catalyst for purification of exhaust gases according to this invention, oxidation treatment and reducing treatment can be applied to the catalyst for purification of exhaust gases in a state where the catalyst installed in the exhaust system of the internal combustion engine.

Furthermore, the method for regenerating catalyst for purification of exhaust gases according to this invention preferably includes (iii) a step of installing a temperature sensor in the catalyst for purification of exhaust gases and the subsequent determination of the degree of degradation of the catalyst for purification of exhaust gases on the base of time functioning and temperature, a thermal sensor; and the stage of initiation of the regeneration process after determining the location of the catalyst in a state of degraded and/or includes (iv) stage determine the state of degradation of the catalyst for purification of exhaust gas using the device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, and the stage of initiation of the regeneration process after determining the location of the catalyst in a state of degraded performance.

The first device for purification of exhaust gases according to this invention includes a pipe for supplying exhaust gases, the catalyst for purification of exhaust gases according to this invention, is placed inside the pipe for supplying exhaust gas temperature sensor installed in the catalyst for purification of exhaust gases, and a control unit for determining the degree of degradation of the catalyst for purification of exhaust gases based on the time of operation and temperature defined by the temperature sensor, and the initiation of the regeneration process using oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and the recovery processing of the settlement of the E. determine the catalyst is in a state of degraded performance.

In addition, a second device for purification of exhaust gases according to this invention includes a pipe for supplying exhaust gases, the catalyst for purification of exhaust gases according to this invention, the catalyst is placed in the pipe for supplying exhaust gases, a device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, and a control unit, which initiates the regeneration process using the catalyst oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and the recovery processing after it is determined that the catalyst for purification of exhaust gas is in a state of degraded unit diagnosing degradation of the catalyst.

Furthermore, the method for purification of exhaust gases according to this invention includes an exhaust gas by bringing the data exhaust gases into contact with the catalyst for purification of exhaust gases according to this invention.

In accordance with this invention, may provide a catalyst for purification of exhaust gases, which can sufficiently be restrained of agregirovannosti noble metal, in order largely to prevent grain growth of the noble metal, even if they are exposed to exhaust gases at a high temperature for a long period of time, whereby the catalyst enables a sufficient deterrent reduction of catalytic activity and the possibility of re-dispersion of the particles of the noble metal in a short time, so a simple way to restore catalytic activity, when grain growth using a catalyst, even if the particles of the noble metal are in an area with a relatively low temperature, and also allows regeneration of the catalyst is simple, even in a state in which it is installed in the exhaust system of the internal combustion engine, the method regeneration of this catalyst for purification of exhaust gases, as well as devices for purifying exhaust gas and method for purification of exhaust gases by using this catalyst for purification of exhaust gases.

Brief description of drawings

Figure 1 is a schematic drawing showing the state of the surface of the oxide layer, in which a noble metal is associated with the cation of the media via an oxygen atom on the surface of the media.

Figure 2 represents a graph is K, shows the relationship between the specific surface area S of the carrier and the standard value X number of noble metal, calculated by equation (1)when the carrier is used Cefor 0.6Zrfor 0.4O2(M=60 mol.%, the lattice constant a=5,304915Å), and as the noble metal Pt (Mnm=195,09). In addition, the shaded area of figure 2 shows the area with the standard value of X is increased two times or less, and the interval from 0.01 to 0.8,

Figure 3 is a photograph of the catalyst for purification of exhaust gases, prepared according to Example 1, obtained using a transmission electron microscope (TEM).

Figure 4 is a photograph of the catalyst for purification of exhaust gases, prepared in Comparative example 1 obtained by using a transmission electron microscope (TEM).

Figure 5 is a graph showing spectra obtained by Fourier transformation of the EXAFS spectra (far fine structure x-ray absorption spectrum) for L3the absorption edge Pt catalysts for purification of exhaust gases, prepared according to Example 1 and Comparative example 1, and a platinum foil and powder PtO2used for comparative purposes.

6 is a graph showing spectra obtained by Fourier-transformation of the JV shall Kirov EXAFS catalysts for purification of exhaust gases, prepared according to Example 2.

Fig.7 is a graph showing spectra obtained by Fourier transformation of the EXAFS spectra of the catalysts for purification of exhaust gases, prepared according to Example 3.

Fig is a graph showing spectra obtained by Fourier transformation of the EXAFS spectra of the catalysts for purification of exhaust gases, prepared according to Example 5.

Fig.9 is a graph showing spectra obtained by Fourier transformation of the EXAFS spectra of the catalysts for purification of exhaust gases, prepared according to Example 7.

Figure 10 is a graph showing the results of testing the speed of re-dispersion of platinum.

Detailed description of preferred embodiments of the invention

Below the invention will be described in detail according to a preferred variant embodiment of the invention.

First, will be the catalyst for purification of exhaust gases according to this invention. In other words, the catalyst for purification of exhaust gases according to this invention is a catalyst for purification of exhaust gases, in which a noble metal is fixed on the carrier oxide of the metal, while

in an oxidizing atmosphere the precious metal is on the surface of the medium in a state of high step is no oxidation, this noble metal is associated with the cation of the media via an oxygen atom on the surface of the carrier, to form a surface oxide layer, and

in a reducing atmosphere, a noble metal is on the surface of the carrier in the metallic state, and the amount of noble metal, open at the surface of the carrier measured by CO chemisorption, is 10% or more per atomic proportion in relation to the total amount of the noble metal attached to the media.

In metal oxide media related to this invention, the value of the binding energy of the 1s orbitals of oxygen in the metal oxide carrier is preferably 531 eV or less, especially preferably ranges from 531 529 eV to eV. When using the oxide with a binding energy of more than 531 eV, the interaction between the noble metal and the carrier becomes sufficiently strong and in an oxidizing atmosphere, the surface oxide layer of the noble metal and the carrier is formed, most likely insufficient. In addition, even if you are using oxidative and reductive processing, as described below, a noble metal on the carrier tends to insufficient re-dispersion. On the other hand, when using a complex oxide with a binding energy less 529 eV, mutual the action between the noble metal and the carrier becomes too strong and even if restorative treatment is used in the regeneration process of the noble metal on the carrier hardly returned to an active state.

Metal oxide carriers satisfying such conditions include, for example, the following oxides:

CeO2-ZrO2-Y2O3:530,04 eV

ZrO2La2O3:530,64 eV

CeO2-ZrO2:530 eV

CeO2-ZrO2La2O3-Pr2O3:529,79 eV.

In addition, in the catalyst for purification of exhaust gases according to this invention, the electronegativity of at least one cation among cations in the metal oxide carrier preferably less electronegativity of the cation zirconium. When the electronegativity of the cations in the metal oxide carrier of the higher electronegativity of the cation of zirconium, the interaction between the noble metal and the carrier becomes strong enough, so it will likely be difficult for effective formation of the surface oxide layer of the noble metal and the carrier in an oxidizing atmosphere and, in addition, a noble metal on the carrier tends to insufficient re-dispersion, even when subjected to oxidizing and reducing treatments, described below.

In addition, such metal oxide media pre is respectfully include a complex oxide of Zirconia and/or alumina and at least one element, selected from the group consisting of alkaline earth elements, rare earth elements and group 3A. These alkaline earth elements include magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), and among them, Mg, Ca and Ba are preferred from the point of view of the trends of the strong interaction and a strong affinity with the noble metal and its oxide. In addition, rare earth elements and elements of group 3A include scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Ga), terbium (Tb), dysprosium (Dy), ytterbium (Yb), lutetium (Lu) and the like, and among them, preferred are La, Ce, Nd, Pr, Y and Sc, and more preferred are La, Ce, Y and Nd with perspective trends of the strong interaction and a strong affinity with the noble metal and its oxide. Such rare earth elements and alkaline earth elements with low electronegativity show a strong interaction with the noble metal and respectively connected to the noble metal through the oxygen atom in an oxidizing atmosphere and prevent evaporation and sintering of the noble metal, whereby substantially restrain the deterioration of the characteristics of the noble metal functioning as an active places.

In these complex oxides are required above the Zirconia and/or acidline and at least one element, selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, to form a complex oxide. In other words, in a state where the Zirconia and/or alumina and at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A simply coexist (for example, when the Zirconia and/or alumina particles and particles of at least one oxide selected from the group consisting of oxides of alkaline earth metals, oxides of rare earth metals and oxides of elements of groups 3A, evenly dispersed), a noble metal on the carrier may be insufficient re-dispersed when using the regeneration process, resulting catalytic activity will be not enough recovered (returned to a previous state).

The ratio (the proportion in the composition) of zirconium dioxide and/or alumina and at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A, the components of such complex oxides, are not limited in a particular way, and the proportion of Zirconia and/or alumina complex oxide is preferably from 5 mass% to 90 mass%, more predpochtitel is but from 10 mass% to 70 mass%. When the proportion of Zirconia and/or alumina complex oxide is less than the above lower limit, the specific surface area becomes small, and accordingly, not only can significantly restrain grain growth of the noble metal, but also particles of the noble metal on the carrier have a tendency to possess enough small sizes, even if implemented method of regeneration according to this invention, described below, or use the regeneration process. On the other hand, if this proportion exceeds the above upper limit, not only is not high enough interaction between the noble metal with the carrier and cannot be suppressed sufficiently and grain growth of the noble metal, but also particles of the noble metal on the carrier have a tendency to possess enough small sizes.

In addition, the metal oxide media may also include, in addition to the above-described complex oxide, alumina, zeolite, Zirconia, etc. as other components. In this case, the portion of the complex oxide in the metal oxide carrier in accordance with this invention is preferably 50 mass% or more.

Media in accordance with this invention particularly preferably comprises a complex oxide of zirconium and at least one the th element, selected from the group consisting of rare earth elements and alkaline earth elements including cerium, and has a structure of fluorite. The structure of fluorite belongs to one of the crystal structures of compounds of the type AX2(A metal element, and X is oxygen), the structure of which is fluorite, having a face-centered cubic lattice, in which the unit cell contains four formula units.

The amount of the metal element contained in the medium, preferably in the range of 51 mol.% up to 75 mol.%, in the calculation of the metal in relation to the number of media. In addition, the amount of such a metal element is preferably in the range from 51,5 mol.% up to 70 mol.%, more preferably in the range of from about 52 mol.% to 65 mol.% and particularly preferably in the range from 52,5 mol.% to 65 mol.%, in the calculation of the metal in relation to the number of media. If the amount of such a metal element is less than 51 mol.%, the number of places of fastening of a noble metal carrier is reduced, and therefore, the noble metal can not gain a foothold in an effective manner, as well as particles of the noble metal on the carrier have a tendency to possess enough small sizes, even if implemented method of regeneration according to this invention, icandy below, or is the process of regeneration. On the other hand, if the amount of such a metal element exceeds 75 mol.%, the proportion of the zirconium complex oxide is likely to be minor, as a consequence, it will be difficult to secure the desired specific surface area, so that, probably, the resistance will be low.

In addition, the amount of cerium contained in component metal element in such media is 90 mol.% or higher, based on the metal, relative to the total number of component metal element. If the amount of cerium is less than 90 mol.%, the metal element, in addition to cerium, can not form a solid solution in the carrier, which leads to the reduction of the specific surface.

In addition, in the medium Zirconia and the metal element present in the form of a solid solution with the formation of particles, homogeneous composition. In General, as CeO2in the media very much reduces its specific surface during high-temperature reduction, the heat resistance tends to decrease, if the media is heterogeneity in the composition of zirconium and cerium. However, due to the fact that the composition of the medium is uniform, as described above, reduction of the specific surface can be prevented. The result of such socialproblems significantly higher thermal stability.

In addition, the shape of the metal oxide carrier in accordance with this invention is not limited in a particular way, the preferred form of powder, because this increases the specific surface area, which increases the catalytic activity. In the case when the metal oxide carrier has the form of powder, grain media (diameter of secondary particles) is not limited to a particular way and preferably is in the range from 5 μm to 200 μm. If the particle diameter is less than the specified lower limit, it is very fine grinding media increases the cost and complicates the treatment of this carrier. On the other hand, if the diameter exceeds the upper limit, there may be difficulties with the stability of the formation on the basis, as described below, the top layer of the catalyst for purification of exhaust gases according to this invention.

Further, the specific surface of such a metal oxide carrier is not limited in a particular way. In addition, the amount of such specific surface area can be calculated as a specific surface according to BET of adsorption isotherms using the equations of isothermal adsorption according to BET.

In addition, the specific surface of this carrier is preferably 1 m2/g or more, more preferably 5 m2/g or more, more preferably 10 m 2/g or more, particularly preferably 15 m2/g or more. If the specific surface is less than the specified lower limit, it is difficult for the securing of the required quantity of the noble metal to provide sufficient catalytic activity. Moreover, when the condition that can be ensured by the resistance of the carrier, the preferred specific surface area of the carrier to a larger value, so that the upper limit of the specific surface area is not limited in a particular way. In addition, since it is important that the specific surface of the carrier was reduced in influencing the atmosphere (high-temperature atmosphere) to fasten the catalytic activity, as a carrier for such a catalyst may also be used by the carrier, the specific surface area of which is reduced prior to the heat treatment with the creation of thermal background. Therefore, it may be also used in the media according to this invention, in which the specific surface area is reduced prior to the heat treatment with the creation of thermal prehistory to less than 80 m2/g and less than 60 m2/, thus the value of such specific surface area can be calculated as a specific surface according to BET of adsorption isotherms using the equations of isothermal adsorption according to BET.

Chrome is also a method of manufacturing a carrier in accordance with this invention is not limited in a particular way, and, for example, the carrier may be manufactured by a method described below. Namely, an aqueous solution containing salts (e.g., nitrate salts of different metals as starting materials, the above-described complex oxide, and surfactant (e.g., nonionic surfactant), if necessary, jointly precipitated complex oxide in the presence of ammonia, the precipitate formed is filtered and washed, then dried and then calcined, resulting in a gain medium comprising a complex oxide.

In addition, in the catalyst for purification of exhaust gases according to this invention is fixed on the carrier noble metal. Although such noble metals include platinum, rhodium, palladium, osmium, iridium, gold, etc., platinum, rhodium and palladium are preferable from the point of view that made the catalyst for purification of exhaust gases exhibits a higher catalytic activity, and platinum with palladium are preferred from the point of view of regeneration.

In addition, the catalyst for purification of exhaust gases according to this invention in an oxidizing atmosphere contains a noble metal, which is located on the carrier surface in the standing high degree of oxidation, and has a surface oxide layer formed by binding a noble metal cation media through oxygen on the surface of the carrier. For this reason, because in the catalyst for purification of exhaust gases according to this invention is a noble metal that serves as the active sites of the catalyst is highly dispersed form on the surface of the carrier and secured on the carrier surface in a stable condition, the catalyst can exhibit a sufficiently high catalytic activity, and it is sufficiently constrained by the grain growth of the noble metal. In addition, the state with high degree of oxidation" in this invention refers to a state in which the noble metal has a valency greater than 0. In addition, "oxidizing atmosphere" in this document refers to a gas atmosphere in which oxygen concentration is 0.5% by volume or more. While the oxidation state of the noble metal on the surface of the carrier, and the status of binding to a carrier can be confirmed using TEM (transmission electron microscopy) and spectral analysis of XAFS (fine structure x-ray absorption spectra).

In addition, in the catalyst for purification of exhaust gases according to this invention in reducing atmospheres is the field number of the noble metal, open on the surface of the carrier measured by CO chemisorption, is 10% or more (more preferably 15%) in atomic % of the total amount of the noble metal attached to the carrier. When the atomic ratio to the amount of noble metal present on the surface of this carrier is less than 10%, the dispersion of the noble metal present on the surface of the medium becomes insufficient, which leads to loss of catalytic activity per amount of precious metal, and also hinders the restoration of catalytic activity through a process of regeneration. In addition, the present invention uses the method described in the publication of unexamined patent application of Japan No. 2004-340637, as a way of CO chemisorption. In addition, "reducing atmosphere" refers to a gas atmosphere in which the concentration of the gaseous reducing agent is 0.1% by volume or more.

In addition, in the catalyst for purification of exhaust gases according to this invention the molar ratio of the cation and the noble metal (cation/noble metal) is preferably 1.5 or more, the cation is open on the surface of the carrier and has an electronegativity less electronegativity of zirconium. If the molar ratio (the cat who he/noble metal) cation and the noble metal is less than the specified lower limit, the part of the noble metal is prone to difficulties of interaction with the media.

In addition, in the catalyst for purification of exhaust gases according to this invention the amount of the noble metal attached to the carrier is preferably in the range from 0.05 mass% to 2 mass% (more preferably from 0.1% by mass to 0.5% by mass relative to the mass of catalyst. If the amount of the noble metal is less than the specified lower limit, the catalytic activity, created by this precious metal will likely not high enough. On the other hand, if the number exceeds the specified upper limit, significantly increasing the cost and will have a tendency to rapid grain growth.

Moreover, in this invention it is preferable that the amount of noble metal, mounted on 100 g of the carrier, does not exceed twice the standard value of X, described below, and ranged from 0.01 g to 0.8 g (more preferably from 0.02 g to 0.5 g, more preferably from 0.05 g to 0.3 g). If the number of such noble metal is less than the specified lower limit, the catalytic activity, created by this precious metal will likely not high enough. On the other hand, if the number exceeds the specified upper limit, the creatures of the NGOs increase costs and will have a tendency to rapid grain growth, as well as the tendency to decrease of catalytic activity per amount of precious metal.

The method of calculating the standard value X is expressed by equation (1):

X=(σ/100)·S/S·N·Mnm·100 (1)

where X is a standard value (unit: g) of the amount of precious metal to 100 g of the carrier; and σ represents the probability (unit: %), with which the metallic element is surrounded by a metal element, the probability of σ is calculated in accordance with equation (2):

σ=M-50 (2)

where M represents the share (unit: mol. %) of the metal element contained in the media; S is the specific surface area (unit: m2/g) media; s represents a single area (unit: Å2/number) on the cation, this single area s is calculated by the equation (3):

[Formula 2]

s={a2+(√2)·a2+(√3/2)·a2}/3·2 (3)

where a represents the lattice constant (unit: Å); N is the Avogadro's number (of 6.02·1023(unit: number); and Mnmrepresents an atomic mass of noble metal attached to the carrier. Preferably the amount of the noble metal, mounted on 100 g of the carrier is from 0.01 g to 0.8 g and not more than twice the standard is th value of X (more preferably greater than 1.5 times, even more preferably equal to it). In addition, when fastened two or more kinds of noble metals, the atomic mass Mnmnoble metals is defined as the value calculated by summing all of the values, calculated by multiplying the atomic mass of the respective noble metals on their share in the total number of the respective noble metals.

This equation (1) defines the ratio between the number of seats stable fixing of the noble metal on the carrier, i.e. the standard value X of the noble metal, and the composition and specific surface of the carrier. If the amount of the noble metal attached to the carrier exceeds more than twice the standard value X calculated by the equation (1)above, the number of atoms of the noble metal to be fixing exceeds the number of places for fixing of the noble metal, in consequence of which there are excess atoms of the noble metal, which can lead to grain growth and reduction of catalytic activity per amount of precious metal. However, if the amount of the noble metal attached to the carrier is equal to or less than twice the standard value X, the noble metal may be easier to re-dispersed, and the catalytic activity per edit the ranks of the amount of the noble metal can be recovered more effectively in the case of the regeneration process according to this invention, described below. If the amount of the noble metal attached to the carrier approaches the standard value of X, the number of atoms of the noble metal, respectively, is approximately equal to the number of seats on the carrier for fixing the precious metal, which further inhibits grain growth and improves regeneration. In addition, if the amount of the noble metal attached to the carrier, equal to standard value of X or less, the number of atoms of the noble metal can be fixed due to the greater number of places for fixing of the noble metal on the carrier, so that noble metal can sufficiently contact with the cations on the surface of the carrier through the oxygen. Therefore, stable noble metal present on the surface of the carrier and secured in a highly dispersed state, which further constrained by the grain growth of the noble metal, and, as a result, increases the catalytic activity per amount of precious metal.

Figure 2 represents a graph showing the relation between the standard quantity X of the noble metal in the above equation (1) and specific surface S. in Addition, this figure 2 represents a graph obtained by calculation when the examples were used e for 0.6Zrfor 0.4O2the media (M=60 mol.%, the lattice constant a=5,E) and Pt (atomic mass Mnm:195,09).

In addition, particularly preferably the conditions in which the amount of the noble metal, mounted on 100 g of the carrier, particularly for long term use, is equal to or less than twice the standard value X is calculated according to equation (1)above, and is in the range from 0.01 g to 0.8, for Example, even after life tests performed by maintaining at a temperature of 1000°C for 5 hours in a simulated gas atmosphere, which is enriched gas (CO (3,75% by volume)/H2(to 1.25% by volume)/H2O (3% by volume)/N2(the remainder)) and depleted gas (O2(5% by volume)/H2O (3% by volume)/N2(the remainder)) was passed with a flow rate of 333 cubic centimeters per minute to 1.5 g of catalyst alternately every 5 minutes, the amount of noble metal, mounted on 100 g of the carrier, preferably satisfies the above conditions.

In addition, in the catalyst for purification of exhaust gases according to this invention, the noble metal is preferably fixed on the carrier in the form of particles of recrystallized grains. The particle diameter of such a noble metal is preferably 3 nm or less, more preferably 2 nm Il is less. When the particle diameter of the noble metal exceeds the specified upper limit, it is likely that it will be difficult to achieve high catalytic activity.

In addition, the method of fastening the noble metal in the carrier is not limited in a particular way, except that the amount of noble metal attached to the carrier is adjusted to satisfy each of the above conditions, and can be used in the following way. For example, the method includes bringing the carrier into contact with an aqueous solution containing a salt (for example, dinitrophenol salt or complex compound (e.g., terminaly complex) of the noble metal is prepared so that the amount of noble metal attached to the carrier, satisfied each of the conditions described above, subsequent drying and subsequent calcination.

Moreover, in the catalyst for purification of exhaust gases according to this invention on the media also preferably secured additional component containing at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A. Through the use of such a component attached to the carrier, the enhanced basicity of the medium, resulting in a more strong interaction between the carrier and mounted thereon a noble metal. This makes possible a greater restraining grain growth of the noble metal, thereby substantially restraining the deterioration of catalytic activity. In addition, when using such a component mounted on the carrier, there is a very strong interaction between the carrier and a noble metal as described above, contributing to the growth of the grains of the precious metal. Even in the case of grain growth during use of the catalyst in accordance with the method for regenerating catalyst for purification of exhaust gases according to this invention, described below, uses the process of regeneration by which the noble metal can be effectively re-dispersed in a short time to restore catalytic activity.

In addition, the element contained in this additional component is preferably at least one element selected from the group consisting of magnesium, calcium, neodymium, praseodymium, barium, lanthanum, cerium, yttrium and scandium, more preferably from neodymium, barium, yttrium and scandium from the point of view as the ability to improve the basicity of the medium to more effectively curb the growth of the grains and facilitate recovery of catalytic activity of the noble metal even in case the e, when was the growth of grains. In addition, an additional component is applicable provided that it contains the above element. His examples include the actual items listed above, the oxides of the above elements, salts of the above items (carbonates, nitrates, citrates, acetates, sulfates), mixtures thereof, etc.

In addition, the number of such additional component attached to the carrier is in the range from 0.5 to 20 (preferably from 1 to 10) in relation to the amount of noble metal based on the metal in a molar ratio of (the number of additional component/amount of precious metal). If this molar ratio is less than the specified lower limit, the amount of the additional component is not sufficient, and therefore improve the basicity of the medium is difficult, there is the possibility of reducing the effect of deterrence sufficient grain growth of the noble metal. On the other hand, if the molar ratio exceeds the upper limit, the specific surface area of the carrier is reduced, which reduces the dispersion of the noble metal.

In addition, the number of such additional component attached to the carrier, per gram of the carrier is preferably from 1,28·10-6to 1.28·10-3mol, more preferably about what 5,13·10 -6up to 5.13·10-4mol, even more preferably from 5,13·10-6to 2.56·10-4mol, and particularly preferably from 5,13·10-6to 1.28·10-4the mole.

In addition, the number of such additional component attached to the outer surface of the carrier, preferably regulated so that the amount of additional component was small, and based on the fact that a small amount of an additional component, it is preferable from the viewpoint of cost, the additional component is preferably fixed at a high density near the outer surface of the carrier. In a state where the medium is in powder form, preferably 80% or more of the component is fixed in the region of 30% from the outer surface to the center of the carrier between the outer surface of the carrier and the center for media.

Moreover, the method of fastening an additional component in the carrier is not limited in a particular way, and, for example, can be used a way of bringing the carrier into contact with an aqueous solution containing a salt of the given element (for example, carbonate, nitrate, acetate, citrate, sulfate) or its complex compound, followed by drying and subsequent calcination. In addition, after the carrier is heat treated, if e is of required and stable, it can be ensured by fixing the above additional material. In addition, when secured this additional component, the order fixing the carrier of the additional component and the noble metal is not limited in a particular way.

In addition, in the catalyst for purification of exhaust gases according to this invention is also on the carrier preferably is fixed iron. Fixation of Fe, thus, leads to the formation of Fe with a noble metal in a reducing atmosphere. On the other hand, in an oxidizing atmosphere, Fe is precipitated as an oxide on the surface and close to the noble metal, and therefore, the grain growth of the noble metal can further be restrained, resulting in significantly hampered by the loss of catalytic activity. In addition, when using the regeneration process performed by the method for regenerating catalyst for purification of exhaust gases according to this invention, described below, provides additional reduction of the particle size of the noble metal serving as active places, and sufficient recovery of catalytic activity.

The amount of iron attached to the carrier is preferably in the range from 0.5 to 12 (more p is edocfile from 0.8 to 12, even more preferably from 1 to 10, particularly preferably from 1 to 5) in a molar ratio (the amount of iron/number of precious metal) to the amount of noble metal based on the metal. If this molar ratio is less than the specified lower limit, it will probably reach a sufficient effect of controlling the growth of grains of the precious metal due to the small amounts of iron. If the ratio exceeds the specified upper limit, the excess is fixed iron is likely to lead to a reduction of the specific surface of the carrier and to the loss of catalytic activity, because iron covers the surface of the noble metal after use over a long period of time. In addition, the value of the upper limit of the molar ratio is more preferably is 3, particularly preferably of 1.5, from the viewpoint of reduction of the specific surface of the carrier and overlapping the surface of the noble metal.

In addition, the lower limit of iron attached to the carrier, is preferably of 1.28·10-4mol, more preferably of 2.05·10-4mol, even more preferably 4,10·10-4mol, particularly preferably 5,13·10-4mol per 100 g of carrier. In addition, the upper limit of iron, Zack is Elenovo on the media, is preferably of 1.23·10-1mol, more preferably 5,13·10-2mol, even more preferably 3,10·10-2mol, particularly preferably of 1.28·10-2mol per 100 g of carrier.

Moreover, in the catalyst for purification of exhaust gases according to this invention, the docking state of iron, fixed to the carrier is not limited in a particular way, and the iron is preferably secured in contact with the noble metal. Such fixing of iron in contact with the noble metal leads to improvement of the effectiveness of deterrence grain growth of the noble metal and when using the regeneration process performed by the method for regenerating catalyst for purification of exhaust gases according to this invention, described below, and to the possibility of more rapid, very fine grinding (re-dispersion) of the particles of the noble metal serving as active places to restore catalytic activity.

In addition, the method of attachment of such iron is not limited in a particular way, and, for example, can be used a way of bringing the carrier into contact with an aqueous solution containing a salt of the given element (for example, carbonate, nitrate, acetate, citrate, sulfate) or its complex compound, followed by drying and further procelian is eat. In addition, the consolidation of such iron may be carried out simultaneously with the fixing of the noble metal, and, for example, can be used a way of bringing the carrier into contact with a mixed solution of the aqueous solution of the salt of the noble metal and an aqueous solution of iron salts followed by drying and subsequent calcination. In addition, the carrier, if required, thermoablative and stabilize, and then it can be ensured by fixing iron and precious metal, etc.

Thus, when the catalyst for purification of exhaust gases according to this invention contains a carrier, a noble metal attached to the carrier, and iron, fixed to the carrier, the docking state (the structure of the catalyst) of the noble metal and iron, fixed to the carrier is not limited in a particular way, and the iron is preferably secured in contact with the noble metal. The consolidation of the iron in contact with the noble metal leads to improvement of the effectiveness of deterrence grain growth of the noble metal, which might result in more fine grinding (re-dispersion) of the particles of the noble metal serving as the active places in the application of the regeneration process, described below.

In addition, the shape of the catalyst is La purification of exhaust gases according to this invention is not limited in a particular way, and can be used in forms such as cell shape monolithic catalyst and form balls of granular catalyst. The base is not limited to a particular way and is selected in accordance with use of the resulting catalyst and the like, can be appropriately used the basis of DPF (Diesel Particular Filter is a particulate filter of the exhaust of diesel engines), solid base, granular base, flat base, etc. In addition, not limited to special properties of the substrate material, and can be used bases made of ceramic, such as cordierite, silicon carbide and mullite, and foundations made from metals such as stainless steel containing chromium and aluminum. Moreover, the method of making such a catalyst is not limited in a particular way, and, for example, in the case of manufacturing the monolithic catalyst is used, respectively, the method which includes forming a coating layer of powder media on a cell basis, formed of cordierite or metal foil, and the subsequent consolidation of a noble metal. In addition, the monolithic catalyst can be made by way of advance fixing of the noble metal powder media and the subsequent formation of the coating is about layer based on the use of such a powder carrier noble metal.

In addition, when a noble metal attached to the carrier in such a catalyst for purification of exhaust gases according to this invention, has an increased grain size due to the use over a long period of time, the application of the method for regenerating catalyst for purification of exhaust gases according to this invention, described below, makes it possible to fine grinding (regrind) particles of the noble metal to restore sufficient catalytic activity. In addition, the particle diameter of the noble metal attached to the carrier, after application of the regeneration process is preferably 3 nm or less (more preferably 2 nm or less), from the viewpoint of achieving high catalytic activity.

So far this document has described the catalyst for purification of exhaust gases according to this invention, as hereinafter will be described a method for regenerating catalyst for purification of exhaust gases according to this invention.

Method for regenerating catalyst for purification of exhaust gases according to this invention is a method characterized by applying oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and recovery processing.

Oxidative atmosphere in which the imp is applied oxidation treatment in accordance with this invention, while it contains a small amount of oxygen, makes possible the oxidation of the noble metal contained in the form of a corresponding number of moles, and the oxygen concentration is preferably 0.5% by volume or more, more preferably from 1% to 20% by volume. If the oxygen concentration is less than the specified lower limit, the re-dispersion of the noble metal on the carrier is most likely insufficient. On the other hand, the higher the oxygen concentration, the better from the viewpoint of oxidation, however, you will need a special device such as an oxygen tank, so that the oxygen concentration was greater than 20% by volume, which is the concentration of oxygen in air and therefore increases costs. In addition, the gas in an oxidizing atmosphere according to this invention, with the exception of oxygen, preferably does not contain a gaseous reducing agent, and preferably the use of nitrogen gas or inert gas.

When the oxidation treatment according to this invention can be used for heating, provided that the temperature of the heating is to a temperature oxidation pinned noble metal, the temperature preferably is in the range from 500°C to 1000°C. If the temperature oxidize Inoi treatment below 500°C, the speed with which the noble metal on the carrier is re-dispersed, becomes extremely low, and re-dispersion is likely to occur sufficiently. On the other hand, if the temperature exceeds 1000°C, the device itself is easily subjected to thermal compression, which leads to loss of catalytic activity.

In addition, the time required for the oxidation treatment according to this invention is selected in accordance with the temperature of the oxidation treatment or the like, If the temperature is low, it takes a long time, and if the temperature is high, you may need a short time. If the temperature of the oxidation treatment is in the range from 500°C to 1000°C, the time spent on stage oxidation treatment is preferably from about one second to one hour. If the oxidation treatment is less than one second, then re-dispersing the noble metal on the carrier is most likely insufficient. On the other hand, if the time exceeds one hour, then re-dispersing the noble metal has a tendency to saturation.

The oxidation treatment according to this invention can be carried out in a special device for processing when removing the catalyst for purification of ychopnh gases from the exhaust system and preferably is performed in a state in which the catalyst installed in the exhaust system of the internal combustion engine. This allows you greatly reduce the number of stages of the oxidation treatment, as well as to ensure the possibility of the circulation exhaust gas after the oxidation treatment, to restore the oxide of the noble metal. Thus, when the oxidation treatment is performed in a state in which a catalyst for purifying exhaust gas is installed in the exhaust system, for example, a large amount of air introduced through the air valve located before the catalytic Converter in the direction of current flow, and the ratio of air to fuel (A/F) in an air-fuel mixture becomes high, or, on the contrary, the quantity of supplied fuel is significantly reduced, resulting in increases the ratio of air to fuel (A/F) in an air-fuel mixture, and then can be executed oxidation treatment. In addition, as the heating means, the catalyst may be heated special heating unit or can be heated using the heat of reaction on the catalyst.

As described above, if the oxidation treatment is performed in a state in which the catalyst installed in the exhaust system, the oxidation treatment can be conducted in real what about the time in accordance with the degree of deterioration of the catalyst efficiency. For example, oxidation treatment may be performed periodically in accordance with the operation time or mileage, or after the catalyst according to the direction of flow of the flow sensor is NOxor the CO sensor to monitor the effectiveness of the catalyst, and if the content of these gases exceeds the standard value, it can be done oxidative processing.

Restorative treatment according to this invention can be accomplished by heating the catalyst in an atmosphere with the presence of a gaseous reductant, such as hydrogen or carbon monoxide. As a result, even if the exhaust gases of the engine are generally in stoichiometric atmosphere, the noble metal can be sufficiently subjected to restoration processing due to the presence of gaseous reductant. In addition, when recovery processing of the gaseous reducing agent may be contained in a small amount, however, the concentration of the gaseous reducing agent is preferably 0.1% by volume or more. If the concentration of the gaseous reductant is less than the specified lower limit, it is difficult for the return of the noble metal on the carrier in the active state. In addition, the gas in the reducing atmosphere in this image is in the shadow, with the exception of a gaseous reducing agent, preferably does not contain a gaseous oxidizing agent and preferably the use of nitrogen gas or inert gas.

Although the temperature of the heating during the reduction processing according to this invention may be a temperature at which there is a restoration of a metal oxide, oxidized by the oxidation treatment, it is preferably 200°C. or above, and the preferred temperature is in the range from 400°C to 1000°C. If the temperature of restorative treatment below 200°C, the oxide of the noble metal on the carrier probably will not be recovered sufficiently. On the other hand, if the temperature exceeds the specified upper limit, it can happen thermal compression of the media itself, which leads to loss of catalytic activity.

In addition, the time required for recovery processing in this invention is selected in accordance with the temperature of the recovery processing, etc. If the temperature is low, it takes a long time, and if the temperature is high, it may be a relatively short time. If the temperature of restorative treatment is 200°C or higher, the time required to perform the stage of recovery processing, the preference is sustained fashion is about from 2 seconds to 5 seconds. If the recovery processing is less than the specified lower limit, the oxide of the noble metal on the carrier is not likely to be recovered sufficiently. On the other hand, if the time exceeds the specified upper limit, a restorative effect on the oxide of the noble metal tends to saturation.

Restorative treatment according to this invention can also be carried out in a special device for processing when removing the catalyst for purification of exhaust gases from the exhaust system, and preferably is performed in a state in which the catalyst installed in the exhaust system of the internal combustion engine. This can significantly reduce the number of restorative stages of processing, and also makes possible the recovery of the oxide of the noble metal by a simple flow of exhaust gas after the oxidation treatment. When the recovery processing is performed in this manner in a state in which a catalyst for purifying exhaust gas is installed in the exhaust system, for example, in the case of the catalyst for purification of exhaust gases of the vehicle, this processing is preferably performed by bringing the catalyst for purification of exhaust gases in contact with the stoichiometric atmosphere with the stoichiometric ratio of equivalents or about kamennoi atmosphere with no oxygen. This provides the ability to use oxygen and restorative treatments, while the catalyst for purification of exhaust gases remains installed in the exhaust system and ensures execution of the regeneration process according to this invention as part of controlling the ratio of air to fuel. In addition, as the heating means, the catalyst may be heated special heating unit or can be heated using exhaust heat.

In addition, although the recovery processing is performed after the oxidation treatment, in the case where oxidation treatment and reducing treatment are each in the form of one stage, oxidation treatment and reducing treatment may be repeated alternately in the regeneration process of this invention, and in this case, oxidation treatment may be performed before restorative treatment or after it. In addition, when the oxidation processing and recovery processing are repeated alternately, the total time of the first treatment and the total time of the last processing is not limited in a particular way.

Furthermore, the method for regenerating catalyst for purification of exhaust gases according to this invention preferably includes a step (I) the mouth of ovci temperature sensor in the catalyst for purification of exhaust gases and determining the degree of degradation of the catalyst for purification of exhaust gases based on the time of operation and temperature, a thermal sensor, and the stage (II) initiation of the regeneration process after determining the location of the catalyst in a state of degraded performance. The inclusion of these stages provides for the use of the regeneration process in addition to determining the state of the degraded catalyst for purification of exhaust gases, whereby the catalyst can be effectively regenerated.

Moreover, this method of regeneration can respectively use the first device for purification of exhaust gases according to this invention, characterized in that it comprises a pipe for supplying exhaust gases, the catalyst for purification of exhaust gases according to this invention, is placed inside the pipe for supplying exhaust gas temperature sensor installed in the catalyst for purification of exhaust gases, and a control unit for determining the degree of degradation of the catalyst for purification of exhaust gases based on the time of operation and temperature defined by the temperature sensor, and the initiation of the regeneration process using the catalyst oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and recovery processing.

This temperature sensor is not limited to the OS is the favorite color by the way and accordingly can be used suitable, widely known temperature sensors capable of determining the temperature state of the catalyst for purification of exhaust gases. In addition, the control unit includes, for example, the engine control unit (ECU).

In addition, the method of determining the degree of degradation of the catalyst is not limited in a particular way, and can be used in the following way. For example, this method of constructing the schema for the relationship between operating time and temperature of the catalyst up until will not require the execution of the regeneration process, by pre-measuring the degree of grain growth (degree of degradation) of the noble metal attached to the catalyst, by using the relationship between the operating time and temperature of the catalyst for purification of exhaust gases and then determine, on the basis of this scheme, the degradation of the catalyst when it is used at a certain temperature for a certain period of time. Also determined the degree of degradation and trigger the regeneration process after determining that the catalyst is in a state of degraded performance.

Moreover, preferably, stage(II) initiation of the regeneration process is controlled so to initiate the regeneration process, when the temperature of the catalyst for purification of exhaust gases is in the range from 500°C to 1000°C, and in this case is the process of regeneration. The implementation of the regeneration process thus provides a more efficient use of the regeneration process.

In addition, it is preferable that the method for regenerating catalyst for purification of exhaust gases according to this invention was determined by the time required for sufficient regeneration of the catalyst for purification of exhaust gases through the application of the regeneration process, on the basis of the relationship between the degree of degradation of the catalyst for purification of exhaust gases and the time of execution of the regeneration process, and then controlled the time of application of the oxidizing and reducing treatments. Thus, the application of the regeneration process makes it possible to reduce unnecessary expenditures of time, etc. and allows a more efficient way to regenerate the catalyst. In addition, this control may be used by the control unit described above. In addition, the method for determining the time required for sufficient regeneration of the catalyst for purification of exhaust gases through the application of the regeneration process, is not limited in a particular way, and the examples included the t method with preliminary measurement time, required for the regeneration process at a given temperature, and the construction of the scheme in the ratio between the time required for the regeneration process, and the temperature at this time with subsequent determination of the time required for the regeneration process, on the basis of this schema.

Furthermore, the method for regenerating catalyst for purification of exhaust gases according to this invention preferably includes a step of determining the state of the degraded catalyst for purification of exhaust gases through the device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, and the stage of initiation of the regeneration process after determining that the catalyst is in a state of degraded performance.

In addition, the method for regenerating catalyst for purification of exhaust gases according to this invention, includes a stage, could therefore use a second device for purification of exhaust gases according to this invention, containing a pipe for supplying exhaust gases, the catalyst for purification of exhaust gases in any of claims 1 to 7, placed inside the pipe for supplying exhaust gases, a device for Diagnostika the Oia degradation of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, and a control unit, which operates in such a way that initiates the regeneration process in which the catalyst is subjected to oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and the recovery processing after detecting the condition of the degraded catalyst for purification of exhaust gases through the device for diagnosing deterioration of characteristics of the catalyst.

Method for regenerating catalyst for purification of exhaust gases according to this invention, comprising the following stages can be performed in the same manner as described regeneration method, which includes stages (I) and (II), except that the device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, is used instead of stage (I), and also used the stage of determining the state of the degraded catalyst for purification of exhaust gases.

In addition, such a device for diagnosing degradation of the catalyst is not limited in a particular way, provided that this device can determine the condition of degraded Hara is the characteristics of the catalyst for purification of exhaust gases. Device for diagnosing deterioration of characteristics of the catalyst includes, for example, a device for diagnosing deterioration of characteristics of the catalyst described in the publication of the patent application of Japan No. 2005-180201. In addition, the control unit includes, for example, the engine control unit (ECU).

Still described method for regenerating catalyst for purification of exhaust gases according to this invention. In this invention the application of the regeneration process, as described above, makes it possible to fine grinding (re-dispersion) of the particles of the noble metal with a larger grain size up to a diameter of 3 nm or less (more preferably up to 2 nm or less). Very fine grinding particles (re-dispersion) of the noble metal attached to the carrier, by applying the regeneration process provides restoration of catalytic activity at a high enough level.

Method for purification of exhaust gases according to this invention is a method characterized in that the exhaust gas is carried out by bringing the exhaust gas into contact with the catalyst for purification of exhaust gases according to this invention. This method of purification of exhaust gas using the catalyst for purification of exhaust gases in this image is in the shadow is not limited in a particular way, provided that the exhaust gases are brought into contact with the catalyst for purification of exhaust gases according to this invention. Furthermore, the method of bringing the exhaust gases into contact with the catalyst for purification of exhaust gases is not limited in a particular way, and can be used in a suitable, well-known methods.

EXAMPLES

Later in this document, the invention will be presented more specifically based on Examples and Comparative examples; however, the invention is by no means limited to the following Examples.

Example 1

To 2000 g of a mixed aqueous solution containing 242,6 g of an aqueous solution of cerium nitrate (containing cerium 28% by weight in the calculation of the CeO2), 157,6 g of an aqueous solution of oxynitride Zirconia (zirconium content of 18% by weight calculated on ZrO2), and 12.6 g of yttrium nitrate and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon), was added 142 g of an aqueous solution of ammonia with a concentration of 25% by weight, and then formed the material was stirred for 10 minutes at room temperature to obtain a product of co-precipitation. Then the product of co-precipitation was filtered and washed, then dried at 110°C, and then progulivali at 1000°C for 5 the Asses in the air, to obtain the media-based complex oxide of cerium-zirconium-yttrium (CeO2-ZrO2-Y2O3). The ratio of the components in the obtained complex oxide was 55 mol.% (CeO2):40 mol.% (ZrO2):5 mol.% (Y2O3). In addition, when using XPS (x-ray photoelectron spectroscopy) was determined by the magnitude of the binding energy of the 1s orbitals of the oxygen of the above complex oxide, which is presented in table 4.

Then 100 g of the carrier was immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried at 110°C and then progulivali at 500°C for 3 hours in the air, receiving a catalyst for purification of exhaust gases (Pt/CeO2-ZrO2-Y2O3) this invention. The amount of platinum attached to the carrier in the resulting catalyst was 1% by weight. In addition, table 1 presents the ratio (Ms/PGM) number of moles of cations, electronegativity less than the electronegativity of the zirconium complex oxide is open on the surface of the carrier, and the number of moles of platinum (PGM) in the resulting catalyst.

In addition, the value of this ratio (Ms/PGM) can be obtained as follows. Namely, first of all, for media based on cerium oxide Ave is polagaetsa, on the outer surface of the carrier cations are present in an amount of 1.54·10-5mol per 1 m2the specific surface of the carrier. If X% is a proportion of the cations, the electronegativity of less than electronegativity of zirconium, on the outer surface of the carrier is present and 1.54·10-5mol · X/100 mol per 1 m2specific surface area of the medium which is taken as the number of moles of cations (Ms), the electronegativity of less than electronegativity of zirconium. In addition, the number of moles of the noble metal for 1 m2the specific surface of the carrier can be obtained through the following equation:

Y=W/(100·S·M)

where Y represents the number of moles of the noble metal, W represents the mass ratio of the noble metal and the carrier (unit: % by mass), S is the specific surface area (unit: m2/g) media, and M is the atomic mass of the noble metal (unit: g/mol). Therefore, the value of the ratio (Ms/PGM) can be estimated by the following equation:

(Ms/PGM)=1,54·10-5·X·S·M/W.

Example 2

To 1500 g of a mixed aqueous solution containing 231 g of an aqueous solution of oxynitride Zirconia (zirconium content of 18% by weight calculated on ZrO2) and 63 g of lanthanum nitrate EXT is ulali 150 g of an aqueous solution of ammonia with a concentration of 25% by mass, and then formed the material was stirred for 10 minutes at room temperature, to obtain a coprecipitation product. Then the product of co-precipitation was filtered and washed, then dried at 110°C, and then progulivali at 1000°C for 5 hours in air to obtain a carrier-based complex oxide of zirconium-lanthanum (ZrO2La2O3). The ratio of the components in the obtained complex oxide was 65% by weight (ZrO2):35% by mass (La2O3). In addition, when using XPS determined the size of the binding energy of the 1s orbitals of the oxygen of this complex oxide, which is presented in table 4. In addition, the catalyst for purification of exhaust gases (Pt/ZrO2La2O3) in this invention was obtained in the same manner as in Example 1, except that there was used the medium obtained in this way. In addition, the value of Ms/PGM in the resulting catalyst are shown in table 1.

Example 3

100 g of the complex oxide of cerium-zirconium-yttrium (CeO2-ZrO2-Y2O3the ratio of the components: 55 mol.% CeO2:40 mol. % ZrO2:5 mol.% Y2O3)obtained by the method similar to the method of manufacturing a carrier according to Example 1 was stirred in water, purified by ion exchange, and was added to 3.38 g of barium nitrate, to obtain a mixed solution. After that, the obtained mixed solution was heated, dried, evaporated who eat moisture and then dried at 110°C, then progulivali at 500°C for 5 hours in air. Then 100 g of the carrier was immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried at 110°C and then progulivali at 500°C for 3 hours in the air, receiving a catalyst for purification of exhaust gases (Pt/Ba/CeO2-ZrO2-Y2O3) this invention. In addition, the number of platinum attached to the carrier in the resulting catalyst was 0.5 wt.%, the number of Ba on 1 g of the carrier was 0,000128 mol, and the molar ratio of Ba and Pt (Ba/Pt) was 5. In addition, the value of Ms/PGM in the resulting catalyst are shown in tables 1 and 3.

Example 4

The catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 3, except that 5,62 g of uranyl nitrate neodymium was added instead of the nitrate of barium. In addition, the value of Ms/PGM in the resulting catalyst are shown in table 3.

Example 5

The catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 3, except that the used aqueous solution of palladium nitrate (Pd concentration: 4% by weight) instead of the aqueous solution dinitrodiphenylamine acidified azo is Noah acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM in the resulting catalyst are shown in tables 1 and 3.

Example 6

The catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 4, except that the used aqueous solution of palladium nitrate (Pd concentration: 4% by weight) instead of the aqueous solution dinitrodiphenylamine, acidified with nitric acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM in the resulting catalyst are shown in table 3.

Example 7

The catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 3, except that the used aqueous solution of rhodium nitrate (Rh concentration: 4% by weight) instead of the aqueous solution dinitrodiphenylamine, acidified with nitric acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM in the resulting catalyst are shown in tables 1 and 3.

Example 8

The catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 4, except that the used aqueous solution of rhodium nitrate (Rh concentration: 4% by weight) instead of the aqueous solution dinitrodiphenylamine, acidified with nitric acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM result in the catalysis of the Torah are given in table 3.

Comparative example 1

The catalyst (Pt/Al2O3) was used for comparison as in Example 1, except that as the carrier used sales of powder of γ-Al2O3(supplied on the market by the company Grace Corp.). In addition, the value of Ms/PGM in the resulting catalyst are shown in tables 1 and 3.

Comparative example 2

The catalyst (Pt/SiO2) was used to compare similarly to Comparative example 1, except that as the carrier used sales of powder SiO2(shipped to market by Aerosil Co. Ltd.).

Comparative example 3

The catalyst for purification of exhaust gases was used to compare similarly to Comparative example 1, except that used an aqueous solution of palladium nitrate (Pd concentration: 4% by weight) instead of the aqueous solution dinitrodiphenylamine, acidified with nitric acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM in the resulting catalyst are shown in table 3.

Comparative example 4

The catalyst for purification of exhaust gases was used to compare similarly to Comparative example 1, except that used an aqueous solution of rhodium nitrate (Rh concentration: 4% by weight) instead of the aqueous solution of dinitrogen is latina, acidified with nitric acid (Pt concentration: 4% by mass). In addition, the value of Ms/PGM in the resulting catalyst are shown in table 3.

Evaluation of characteristics of the catalysts for purification of exhaust gases, prepared according to Examples 1 to 3, 5 and 7 and Comparative example 1

<Studies of noble metal using TEM and XAFS>

First of all, the catalysts prepared according to Examples 1 to 3 and Comparative example 1 were subjected to an oxidizing treatment at 800°C for 5 hours in an oxidizing atmosphere containing O2(20% by volume) and N2(80% by volume). In addition, the catalysts prepared according to Examples 5 and 7, were subjected to oxidation treatment at 1000°C for 5 hours in an oxidizing atmosphere containing O2(20% by volume) and N2(80% by volume). Then, each catalyst prepared according to Example 1 and Comparative example 1, after the oxidation treatment was investigated using TEM (transmission electron microscopy). In addition, each catalyst prepared according to Examples 1 to 3, 5 and 7 and Comparative example 1, after the oxidation treatment was investigated by using the method of XAFS (studies of the fine structure x-ray absorption spectra) for noble metals (Pt, Pd, Rh), performed by the local structure analizoru atoms of the noble metal and watched the state of the noble metal on the carrier. Pictures taken with TEM presented in figure 3 (Example 1) and 4 (Comparative example 1), and the results obtained by XAFS measurements, presented in figure 5 (Example 1 and Comparative example 1), 6 (Example 2), 7 (Example 3), Fig (Example 5) and Fig.9 (Example 7). In addition, figure 5 presents the spectra obtained by Fourier transformation of the EXAFS spectra at the L3the absorption edge Pt catalysts prepared according to Example 1 and Comparative example 1, and Pt foil and powder PtO2.

<a Dispersion of noble metals after recovery processing>

The catalysts prepared according to Examples 1 to 3, 5 and 7 and Comparative example 1 were subjected to reducing treatment at 400°C in a reducing atmosphere containing H2(10% by volume) and N2(90% by volume), and then evaluated the dispersion of the noble metals by the method of CO chemisorption described in JP 2004-340637A. The results obtained are presented in table 1. In addition, when the magnitude of dispersion (%) increases the proportion of noble metal, open at the surface, indicating the presence of a noble metal in a highly dispersed metallic state.

Table 1
Catalyst The binding energy of the 1s orbitals of the oxygen carrier [eV]The electronegativity of the cation of the metal oxide mediaMs/PGMThe dispersion of the noble metal, a certain way chemisorption of CO (%)Surface oxide layer between the noble metal and the media
Example 1Pt/CeO2-ZrO2-Y2O3530,04Ce:1,12
Zr:1,33
Y:1,22
9,043Formed
Example 2Pt/ZrO2La2O3530,64La:1,10
Zr:1,33
8,628Formed
Example 3Pt/Ba/CeO2-ZrO2-Y2O3530,04Ce:1,12
Zr:1,33
Y:1,22
Ba:0,89
1848Formed
Example 5Pd/Ba/CeO2-ZrO2-Y 2O3530,04Ce:1,12
Zr:1,33
Y:1,22
Ba:0,89
9,820Formed
Example 7Rh/Ba/CeO2-ZrO2-Y2O3530,04Ce:1,12
Zr:1,33
Y:1,22
Ba:0,89
9,521Formed
Comparative example 1Pt/γ-Al2O3531,40Al:1,610(*)2Not formed
(*) in the table indicates that the cation electronegativity is less than the electronegativity of zirconium, is not present.

The results presented in figure 3 and 4 show that the Pt particles was not observed in the media when the TEM measurements in the case of the catalyst for purification of exhaust gases according to this invention (Example 1). In addition, in the catalyst for purification of exhaust gases according to this invention (Example 1) the presence of Pt was confirmed by EDX analysis. Accordingly, in the case of the catalyst for the cleaning of exhaust gases according to this invention (Example 1) is installed, that Pt is fixed at a very high dispergirovannom condition. On the other hand, in the case of the comparative catalyst for purification of exhaust gas (Comparative example 1) was observed in the Pt particles ranging in size from 3 nm to 150 nm, and therefore it is established that Pt is fixed in an aggregated state.

In addition, since the results presented in figure 5 show that in the catalyst for purification of exhaust gases according to this invention (Example 1) peak is observed, corresponding connection Pt-O confirms that the Pt is in a state with a high degree of oxidation (valence +2 and +4). Furthermore, since the catalyst for purification of exhaust gases (Example 1) peak is observed, corresponding connection Pt-O-Ce confirmed that Pt is associated with the Ce, which is the cation media, through oxygen. In addition, the coordination number of communication Pt-O-Ce was assessed as amounting to 3.5. This value is small compared with the coordination number 12 in the case where Pt is completely dissolved in the carrier with the formation of solid solution, and therefore confirms that the Pt is on the carrier surface and forms a surface oxide layer with a carrier. Similarly, as is evident from the results shown in Fig. 6 through 9, it is confirmed that the noble metal is associated with the cation of the medium sour through the od in the catalyst for purification of exhaust gases according to Examples 2, 3, 5 and 7. In addition, because the coordination number is small in comparison with the coordination number when the noble metal is completely dissolved with the formation of solid solution confirms that the noble metal forms a surface oxide layer with a carrier in the catalysts obtained in Examples 2, 3, 5 and 7. On the other hand, as in comparative catalyst for purification of exhaust gas (Comparative example 1) was observed a large peak caused by the connection Pt-Pt confirms that the Pt is in the metallic state in the form of large particles. In addition, the coordination number of communication Pt-Pt was evaluated as a component 12, whereby it is confirmed that Pt is in the form of large particles with a size of at least 20 nm.

Moreover, as is evident from the results presented in table 1, confirmed that the magnitude of dispersion is low and amounts to only 2% in the comparative catalyst for purification of exhaust gas (Comparative example 1), while it is confirmed that the magnitude of dispersion in the catalysts for purification of exhaust gases according to this invention (Examples 1 to 3, 5 and 7) is very high and constitute 20% or more, whereby it is confirmed that the noble metal is highly dispersed state in the catalyst for purification of exhaust gases is about this invention.

From these results it was established that in the catalysts for purification of exhaust gases according to this invention (Examples 1 to 3, 5 and 7) in an oxidizing atmosphere the precious metal is on the surface of the medium in a state with a high degree of oxidation and is associated with the cation of complex oxide through oxygen, open at the surface of the carrier, with the formation of the surface oxide layer of the noble metal and the carrier, and in a reducing atmosphere, the noble metal is in a state of highly dispersed metal.

Evaluation of characteristics of the catalysts for purification of exhaust gases, prepared according to Examples 3 to 8 and Comparative examples 1, 3 and 4

<evaluation of the average particle diameter of the noble metal after testing the durability>

First of all, one of the catalysts for purification of exhaust gases, prepared according to Examples 3 to 8 and Comparative Examples 1, 3 and 4 were subjected to molding to seal the powder at a pressure of 1 t/cm2when using cold isostatic molding (CIP), and then the resulting material was ground to obtain a particle size of from 0.5 mm to 1 mm, to obtain granulated catalysts. Then, each of the thus obtained granular catalysts were placed in a reaction vessel and treated at a temperature of 950°C for 5 hours, alternately passing the enriched and depleted gases, shown in table 2, every 5 minutes so that their consumption was 500 cm3/min to 3 g of the catalyst in the reaction vessel, through which he created the conditions for grain growth of the noble metal on the carrier (life test). After these tests the durability was evaluated average particle diameter of the noble metal, and the results are presented in table 3. When this average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A.

Table 2
COO2CO2N2
Enriched gas [units:%]5010Rest
Depleted gas [units:%]0510Rest

As also seen from the results presented in table 3 confirms that the grain growth of blagar the underwater metal more significantly constrained in the catalyst for purification of exhaust gases according to this invention (Examples 3 to 8).

Evaluation of characteristics of the catalysts for purification of exhaust gases, prepared according to Examples 1 and 2 and Comparative examples 1 and 2

<Test re-dispersion of platinum>

Test example 1

The catalyst prepared according to Example 1 was subjected to heat treatment at 1000°C for 5 hours in an atmosphere containing 3% by volume CO and 97% by volume of N2to create conditions for the growth of grains of platinum on the carrier. Then the catalyst thus increased the size of the grains were subjected to oxidation processing (the process of re-dispersion) when C for 30 minutes in an oxidizing atmosphere containing 20% by volume of O2and 80% by volume of N2to try re-dispersing platinum. It was estimated the average particle diameter of platinum after life tests and the average particle diameter of platinum after re-dispersion, the estimation results are presented in table 4. The average particle diameter of platinum was estimated by the method of CO chemisorption described in JP 2004-340637 A. In addition, this re-dispersion and restoration pre-treatment, in accordance with the results of measurements by the method of CO chemisorption, achieved oxidative and reductive treatments of each of the catalyst for purification of exhaust gases, which is constitute the regeneration process.

Test example 2

Test the dispersion of platinum was performed in the same manner as in Test example 1, except that the temperature of the processing in the process of re-dispersion was set at 500°C. the results Obtained are presented in table 4.

Test example 3

Test the dispersion of platinum was performed in the same manner as in Test example 1, except that the temperature of the processing in the process of re-dispersion was set at 1000°C. the results Obtained are presented in table 4.

Test example 4

Test the dispersion of platinum was performed in the same manner as in Test example 1, except that in the process of re-dispersion temperature processing was set at 600°C, and the oxygen concentration was 3%. The results obtained are presented in table 4.

Test example 5

Test the dispersion of platinum was performed in the same manner as in Test example 1, except that used a catalyst prepared according to Example 2. The results obtained are presented in table 4.

Comparative test example 1

Then test the dispersion of platinum was performed in the same manner as in Test example 1, except that the used catalyst prepara is built in Comparative example 1, and platinum on the carrier was subjected to conditions conducive to the growth of the grains, when using the catalyst prepared in Comparative example 1, and heat-treated platinum at 800°C for 5 hours. The results obtained are presented in table 4.

Comparative test example 2

Test the dispersion of platinum was performed in the same manner as in Comparative test example 1, except that the temperature of the processing in the process of re-dispersion was set at 500°C. the results Obtained are presented in table 4.

Comparative test example 3

Test the dispersion of platinum was performed in the same manner as in Comparative test example 1, except that used the catalyst prepared in Comparative example 2. The results obtained are presented in table 4.

Table 4
CatalystThe binding energy of the 1s orbitals of the oxygen carrier [eV]The average diameter of the Pt particles after life tests [nm]The average diameter of the Pt particles after re-dispersion [nm]The temperature of the process the sa re-dispersion [°C] The oxygen concentration at the re-dispersion [% by volume]
Test example 1Pt/CeO2-ZrO2-Y2O3
(Example 1)
530,0413,63,380020
Test example 2Pt/CeO2-ZrO2-Y2O3
(Example 1)
530,0413,610,250020
Test example 3Pt/CeO2-ZrO2-Y2O3
(Example 1)
530,0413,64,6100020
Test example 4Pt/CeO2-ZrO2-Y2O3
(Example 1)
530,0413,68,76003
Test example 5Pt/ZrO2La2O3
(Example 2)
530,6414,2the 3.880020
Cf-
positive test example 1
Pt/Al2O3
(Comparative example 1)
531,4012,215,080020
Comparative test example 2Pt/Al2O3
(Comparative example 1)
531,4012,212,850020
Cf-
positive test example 3
Pt/SiO2
(Comparative example 2)
532,8415,745,080020

As is evident from the results presented in table 4, in accordance with the method of regeneration (Test examples 1 to 5) according to this invention, it is confirmed that the platinum particles formed by the growth of grains during life tests, be very small according to their average diameter is in the process of their REP is REGO dispersion. On the other hand, confirmed that the average particle diameter of platinum does not become small in the Comparative test examples 1 to 3, even when using the process of re-dispersion, and that the average particle diameter, on the contrary, becomes more in the process of re-dispersion in the case of the Comparative test examples 1 and 3. The authors of the present invention believe that this is due to the fact that the value of the binding energy of the 1s orbitals of oxygen in the media more and 531 eV, the positive effect of the process of re-dispersion is not implemented due to the weak interaction between platinum and media, and, on the contrary, grain growth of platinum contributes to a high temperature oxidizing atmosphere.

<Test speed re-dispersion of platinum>

Test example 6

Initially, the catalyst prepared according to Example 1 (Pt/CeO2-ZrO2-Y2O3), was subjected to heat treatment at 950°C for 5 hours in an atmosphere containing 3% by volume CO and 97% by volume of N2to stimulate the growth of grains of platinum on the carrier to achieve the average particle diameter of 6.7 nm (life test). Then the catalyst, which is increased in this way the size of grains of platinum, were subjected for 100 minutes alternately restorative treatment at 700°C 60 Sekou is on in the atmosphere, containing 3% by volume of H2and 97% by volume of He and oxidative processing (the process of re-dispersion) at 700°C for a duration of 10 seconds in an atmosphere containing 20% by volume of O2and 80% by volume of He to attempt to re-dispersing platinum. During processing was measured XANES spectra (near-fine structure x-ray absorption) at L3-absorption edge Pt every one second, to estimate the average particle diameter of platinum at the peak height, called white line XANES spectrum, and to check for changes in the mean diameter of platinum particles over time during processing. The results are presented in table 10.

Test example 7

Test the speed of re-dispersion of platinum was performed in the same manner as in Test example 6, except that the temperature at which alternately described above was carried out restorative treatment and oxidation treatment, was set at 600°C. the results Obtained are presented in table 10.

As is evident from the results shown in Fig. 10, in accordance with the method of regeneration according to this invention (Test examples 6 and 7), re-dispersion of platinum is alternately repeating the above-described restoration processing and oxidation treatment; the average diameter of the particles of the platinum particles is reduced to 3.6 nm in Test example 6 and up to 2.9 nm in Test example 7. In addition, the rate of re-dispersion of platinum was high when the treatment temperature was 700°C, compared with a case when the treatment temperature was 600°C.

Thus, even when short-term process of re-dispersion with a duration of 10 seconds, repeat the process of re-dispersion leads to a small average diameter of the platinum particles, and thus, the regeneration process of this invention can be performed as part of the control the ratio of air to fuel by providing efficient regeneration of the catalyst in a state in which the catalyst installed in the exhaust system of the internal combustion engine. Therefore, it is confirmed that in accordance with the method of regeneration according to this invention a high catalytic activity can be fixed for a long period of time without the need for special maintenance.

Example 9

To 2000 g of a mixed aqueous solution containing 233 g of an aqueous solution of cerium nitrate (containing cerium 28% by weight in the calculation of the CeO2), 152 g of an aqueous solution of oxynitride Zirconia (zirconium content of 18% by weight calculated on ZrO2), 14 g of yttrium nitrate and 10 g seionage the CSOs surfactants (shipped to market by Lion Corporation, trade name: Leocon), was added 200 g of an aqueous solution of ammonia with a concentration of 25% by weight, and then formed the material was stirred for 10 minutes at room temperature to obtain a product of co-precipitation. Then the product of co-precipitation was filtered and washed, then dried at 110°C, and then progulivali at 1000°C for 5 hours in air to obtain a carrier-based complex oxide of cerium-zirconium-yttrium (CeO2-ZrO2-Y2O3). In addition, the ratio of the components in the obtained complex oxide (CZY) was 68% by weight (CeO2):28%, by weight (ZrO2):4%, by weight (Y2O3). In addition, when using XPS (x-ray photoelectron spectroscopy) was determined by the magnitude of the binding energy of the 1s orbitals of the oxygen of the above complex oxide, which is presented in table 5.

Then 100 g of the obtained carrier was immersed in water purified by ion exchange and mixed, then added to 3.38 g of barium nitrate, to obtain a mixed solution. After that, the obtained mixed solution was heated, dried by evaporation and then dried at 110°C, after which he progulivali at 500°C for 5 hours in air, ensuring the fixing of the carrier an additional component containing barium, to obtain a carrier with a fixed additional to what momentum. Then the resulting carrier with an additional component was immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried at 110°C and then progulivali at 500°C for 3 hours in the air, receiving a powdered catalyst for purification of exhaust gases according to this invention, in which the carrier is fixed Pt and an additional component containing Ba. Powder catalyst for purification of exhaust gases according to this invention, thus obtained, was subjected to molding to seal the powder at a pressure of 1 t/cm2when using cold isostatic molding (CIP) and then the resulting material was crushed to a particle size of from 0.5 mm to 1 mm, to obtain a granular catalyst. The number of Pt mounted on the carrier in the resulting catalyst for purification of exhaust gas was 0.5% by mass, the amount of Ba, mounted on the carrier in an additional component was 0,000128 mol per 1 g of the carrier, and the molar ratio (Ba/Pt) the amount of Ba in the additional component and the amount of Pt was 5.

Example 10

The granular catalyst for purification of exhaust gases according to this invention were prepared as in Example 9 except what 5,62 g of uranyl nitrate neodymium was added instead of the nitrate of barium. Number of assigned Pt and Ba in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 11

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 9, except that the number of added barium nitrate was changed to 0,677, the number of assigned Pt and Ba in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 12

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 9, except that the number of added barium nitrate was changed to 1.35, the number of assigned Pt and Ba in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 13

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 9, except that the number of added barium nitrate was changed to 6,77, the number of assigned Pt and Ba in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 14

The granular catalyst for purification of exhaust gases according to this invention prigotovit is whether analogously to Example 9, except that the number of added barium nitrate was changed to 0,677 g, and was added into a mixed solution of 1.05 g of iron nitrate. Number of assigned Pt, Ba and Fe in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 15

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 14, except that the added amount of the aqueous solution dinitrodiphenylamine, acidified with nitric acid, was added to a mixed solution of barium nitrate and iron nitrate to accommodate Pt, Ba and Fe in the media at the same time. Number of assigned Pt, Ba and Fe in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 16

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 12, except that the temperature of annealing in the preparation of the medium was changed to 1000°C 700°C. the number of fixed Pt and Ba in the resulting catalyst for purification of exhaust gases is presented in table 5.

Example 17

Comparative catalyst for purification of exhaust gases produced when using the media, the same media used in Example 9. Namely, 100 g novtel is immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried at 110°C and then progulivali at 500°C for 3 hours in the air, getting a comparative powder catalyst for purification of exhaust gases, in which Pt is fixed on the carrier. The amount of platinum attached to the carrier in the resulting catalyst was 0.5% by weight. In addition, the catalyst for purification of exhaust gases, thus obtained, was subjected to molding to seal the powder at a pressure of 1 t/cm2when using cold isostatic molding (CIP), and then the resulting material was crushed to a particle size of from 0.5 mm to 1 mm, to obtain a granular catalyst. The amount of platinum attached to the carrier, the resulting catalyst for purification of exhaust gases is presented in table 5.

Comparative example 5

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 17, except that as the carrier used sales of powder of γ-Al2O3(supplied on the market by the company Grace Corp.). The number of Pt mounted on the carrier, the resulting catalyst for purification of exhaust gases is presented in table 5.

Each of the granular catalysts prepared according to Examples 9 to 17 and Comparative example 5 were tested on durability. When this catalyst was placed in a reaction vessel and treated at a temperature of 950°C for 5 hours, alternately passing the enriched and depleted gases listed in table 2, every 5 minutes so that their consumption was 500 cm3/min to 3 g of the catalyst in the reaction vessel, through which he created the conditions for grain growth of the noble metal on the carrier (life test). After these tests the durability was evaluated average particle diameter of the noble metal, and the results are presented in table 5. The average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A.

<Test re-dispersion of platinum>

Each of the catalysts for purification of exhaust gases, prepared according to Examples 9 to 17 and Comparative example 5 were subjected to oxidation processing (the process of re-dispersion) at 750°C for 30 minutes in an atmosphere containing 20% by volume of O2and 80% by volume of N2to try re-dispersing platinum. The average particle diameter of the noble metal in the catalysts for purification of wyhl the Phnom gases after such a process of re-dispersion are presented in table 5. The average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A. This re-dispersion and restoration pre-treatment, in accordance with the results of measurements by the method of CO chemisorption, achieved oxidative and reductive treatments of each of the catalyst for purification of exhaust gases that make up the process of regeneration.

As is evident from the results presented in table 5, it is confirmed that in the catalysts for purification of exhaust gases according to this invention (Examples 9 to 17, especially the Examples 9 to 16) grain growth of the noble metal is restrained in a substantial way. In addition, it is confirmed that in the catalysts for purification of exhaust gases according to this invention (Examples 9 to 17, especially the Examples 9 to 16) the particle size of the noble metal is significantly reduced when using the regeneration method according to this invention, which provides restoration of catalytic activity in a simple way.

Example 18

To 2000 g of a mixed aqueous solution containing 242,6 g of an aqueous solution of cerium nitrate (containing cerium 28% by weight in the calculation of the CeO2), 157,6 g of an aqueous solution of oxynitride zirconium(with a zirconium content of 18 % by weight calculated on ZrO2), 2.6 g of yttrium nitrate and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon), was added 142,2 g of an aqueous solution of ammonia with a concentration of 25% by mass, and then formed the material was stirred for 10 minutes at room temperature to obtain a product of co-precipitation. Then the product of co-precipitation was filtered and washed, then dried at 110°C, and then progulivali at 1000°C for 5 hours in air to obtain a carrier-based complex oxide of cerium-zirconium-yttrium (CeO2-ZrO2-Y2O3). In addition, the ratio of the components in the obtained complex oxide (CZY) accounted for 67.9% of the mass (CeO2):28,4% by weight, (ZrO2):3.7 percent by weight (Y2O3).

Then 100 g of the obtained carrier was immersed in water purified by ion exchange and mixed, then added 2,092 g of iron nitrate, to obtain a mixed solution. After that, the obtained mixed solution was heated, dried by evaporation and then dried at 110°C, after which he progulivali at 500°C for 5 hours in air, ensuring the fixing of the carrier iron to get the media with additional fixed component.

Then the resulting carrier with an additional component was immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried PR the temperature of 110°C and then progulivali at 500°C for 3 hours in air, receiving a powdered catalyst for purification of exhaust gases according to this invention, in which the carrier is fixed Pt and Fe. Powder catalyst for purification of exhaust gases according to this invention, thus obtained, was subjected to molding to seal the powder at a pressure of 1 t/cm2when using cold isostatic molding (CIP) and then the resulting material was ground to obtain a particle size of from 0.5 mm to 1 mm, to obtain a granular catalyst. The number of Pt mounted on the carrier in the resulting catalyst for purification of exhaust gases was 1% by weight, the amount of Fe, mounted on the carrier, was 0,00513 mole per 100 g of the carrier, and the molar ratio (Fe/Pt) number of Fe and the amount of Pt was 1 per metal.

Example 19

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 1, except that the amount of added iron nitrate was changed to at 1,046 g, and the amount of Pt mounted on the carrier was changed to 0.5% by weight. Number of assigned Pt and Fe in the resulting catalyst for purification of exhaust gases and the molar ratio of Fe and Pt are presented in table 8.

Example 20

The granular catalyst for purification of exhaust gases is anomo invention were prepared analogously to Example 19, except that the amount of added iron nitrate was changed to 2,092, the number of assigned Pt and Fe in the resulting catalyst for purification of exhaust gases and the molar ratio of Fe and Pt are presented in table 8.

Example 21

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 19, except that the amount of added iron nitrate was changed to 5,229, the number of assigned Pt and Fe in the resulting catalyst for purification of exhaust gases and the molar ratio of Fe and Pt are presented in table 8.

Example 22

The granular catalyst for purification of exhaust gases, also having fixed therein the component containing Ba, according to this invention were prepared analogously to Example 19, except that the amount of added iron nitrate was changed to at 1,046 g, and also added 0,677 g of barium nitrate. Number of assigned Pt, Fe and Ba in the resulting catalyst for purification of exhaust gases is presented in table 8.

Example 23

The granular catalyst for purification of exhaust gases, also having mounted thereon a fixing component containing Ba, according to this invention, were prepared analogously to Example 22, except that in addition to nitrate and iron nitrate b is Riya also added an aqueous solution dinitrodiphenylamine, acidified with nitric acid. Number of assigned Pt, Fe and Ba in the resulting catalyst for purification of exhaust gases is presented in table 8.

Example 24

Comparative catalyst for purification of exhaust gases produced when using the same media that was used in Example 18. Namely, 100 g of the carrier was immersed in an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), was filtered and washed, then dried at 110°C and then progulivali at 500°C for 3 hours in the air, getting a comparative powder catalyst for purification of exhaust gases, in which platinum is fixed on the carrier. The number of Pt mounted on the carrier in the resulting catalyst was 1% by weight. In addition, a comparative catalyst for purification of exhaust gases, thus obtained, was subjected to molding to seal the powder at a pressure of 1 t/cm2when using cold isostatic molding (CIP), and then the resulting material was crushed to a particle size of from 0.5 mm to 1 mm, to obtain a granulated catalyst.

Example 25

The granular catalyst for purification of exhaust gases according to this invention were prepared analogously to Example 24, C is the exception that the number of Pt mounted on the carrier was changed to 0.5 % by weight. The number of Pt mounted on the carrier, the resulting catalyst for purification of exhaust gases is presented in table 8.

Example 26

Comparative granulated catalyst for purification of exhaust gases prepared analogously to Example 19, except that the amount of added iron nitrate was changed to 0,523, the number of assigned Pt and Fe in the resulting catalyst for purification of exhaust gases and the molar ratio of Fe and Pt are presented in table 8.

Example 27

Comparative granulated catalyst for purification of exhaust gases prepared analogously to Example 19, except that the amount of added iron nitrate was changed to 15,69, the number of assigned Pt and Fe in the resulting catalyst for purification of exhaust gases and the molar ratio of Fe and Pt are presented in table 8.

<Test for durability (I)>

Each of the granular catalysts prepared according to Examples 18 and 24 were subjected to test for durability (I). Namely, the catalyst was kept at a temperature of 950°C for 10 hours in a gas atmosphere containing H2(3% by volume) and N2(97% by volume), to promote grain growth of Pt on the media (life test (I)). The average diameter is R Pt particles after the durability test together with the results presented in tables 6 and 7. In addition, the average diameter of the Pt particles was estimated by the method of x-ray diffraction (XRD) and the method of CO chemisorption described in JP 2004-340637 A. the Average diameters of the particles, evaluated by the method of x-ray diffraction are presented in table 6, and the average diameters of the particles, evaluated by way of the chemisorption of CO are presented in table 7.

As can be seen from the results shown in table 6 confirms that the grain growth is restrained by the presence of Fe near Pt even in a simple enriched atmosphere. In addition, the catalyst prepared according to Example 18, the diffraction line Pt (1,1,1) was shifted to a higher angle and Fe was dissolved in Pt as an impurity with the formation of solid solution.

<Test regeneration (I)>

Each of the catalysts for purification of exhaust gases, prepared according to Examples 18 to 24, after the durability test (I) was subjected to oxidation treatment (the process of re-dispersion) at 800°C for one minute in an atmosphere containing 20% by volume of O2and 80% by volume of He to attempt to re-dispersing Pt. The average particle diameter of the noble metal in the catalysts for purification of exhaust gases after such a process of re-dispersion is presented in table 7. The average particle diameter of the noble metal was evaluated with the special chemisorption of CO, described in JP 2004-340637 A. Such a re-dispersion and restoration pre-treatment, in accordance with the results of measurements by the method of CO chemisorption, achieved oxidative and reductive treatments of each of the catalyst for purification of exhaust gases that make up the process of regeneration.

As shown in table 7, after life tests in an enriched atmosphere of the particle diameter of Pt in the catalyst for purification of exhaust gases, prepared according to Example 18 was rated as exceeding the diameter of the Pt particles in the catalyst prepared according to Example 24. These results, as evident from the values of the diameter of the Pt particles shown in table 6 and are single-digit number, suggest that CO cannot join remote from the center of the surface active places for the reason that dissolved Fe as an impurity with the formation of solid solution in Pt, is associated with the measurement method (method of CO chemisorption). As a consequence, the diameter of the Pt particles listed in table 7, are not true diameters. In addition, after regeneration of the catalyst according to Example 18, the diameter of the Pt particles is smaller than that of the catalyst according to Example 24, and this is due to the fact that the iron oxide is deposited from the active places with an educated alloy and, consequently, create the tsya additional surface Pt, due to the increasing number of adsorbed CO. These results confirmed that the catalyst prepared according to Example 18, the growth of the Pt grains suspended in enriched atmosphere and the active space then regenerated by the regeneration process.

<Test for durability (II)>

Each of the granular catalysts prepared according to Examples 19 to 23 and 25 to 27, were tested on durability. In other words, the catalyst was placed in a reaction vessel and treated at a temperature of 950°C for 5 hours, alternately passing the enriched and depleted gases listed in table 2, every 5 minutes so that their consumption was 500 cm3/min to 3 g of the catalyst which created conditions for grain growth of the noble metal on the carrier (life test (II)). The average diameter of the Pt particles after such tests on the durability was evaluated by the method of CO chemisorption described in JP 2004-340637 A; the results are presented in table 8.

<Test regeneration (II)>

Each of the catalysts for purification of exhaust gases, prepared according to Examples 19 to 23 and 25 to 27 after durability test (II), was subjected to oxidation treatment (the process of re-dispersion) at 750°C for 30 minutes in the atmosphere, containing 20% by volume of O2and 80% by volume of N2to try re-dispersing Pt. The average particle diameter of the noble metal in the catalysts for purification of exhaust gases after such a process of re-dispersion is presented in table 8. The average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A. Such a re-dispersion and restoration pre-treatment, in accordance with the results of measurements by the method of CO chemisorption, achieved oxidative and reductive treatments of each of the catalyst for purification of exhaust gases that make up the process of regeneration.

The results presented in table 8 also indicate that in the catalysts for purification of exhaust gases according to this invention prepared according to Examples 19 to 23, in which the molar ratio of Fe and Pt (Fe/Pt) is in the range from 0.8 to 12 restrains the growth of grains of Pt after life tests in enriched/depleted in the atmosphere as compared with the catalysts for purification of exhaust gases, prepared according to Example 25, in which the value of Fe/Pt is 0, and in Examples 26 and 27, in which the value of Fe/Pt is outside the interval from 0.8 to 12. In addition, it is confirmed that in the catalysts for purification of wyhl the Phnom gases according to this invention (Examples 19 to 23) the diameter of the Pt particles after the regeneration process has a small value, so it may be sufficiently restored catalytic activity, resulting in the possibility of obtaining high catalytic activity. In addition, it is confirmed that when the amount of Fe, mounted on the carrier, small, as in the catalyst prepared according to Example 26, the effect of controlling the growth of Pt grains and fine grinding particles in the regeneration process are likely to be insufficient, while when the amount of Fe, mounted on the carrier, large specific surface of the carrier tends to decrease, as it takes place in the catalyst prepared according to Example 27. In addition, the results for the catalysts for purification of exhaust gases, prepared according to Examples 22 and 23, confirm that Ba (additional component) mainly fixed before fixing the Pt or even simultaneously with the consolidation of Pt.

The above results (tables 6 through 8) for a catalyst for purification of exhaust gases according to this invention (Examples 18 to 27, especially Examples 18 through 23) confirm that the grain growth of the noble metal is restrained in a substantial way. In addition, it is confirmed that the noble metal in the catalysts for purification of exhaust gases according to this invention (Examples 18 to 27, especially Examples 18 through 23) to access the exact extent is crushed when using the regeneration method according to this invention, that provides a simple way of restoring catalytic activity.

Example 28

First of all produced a complex oxide of cerium-zirconium-praseodymium-lanthanum (CeO2-ZrO2-Pr2O3La2O3) as a carrier. In other words, first 217,3 g of an aqueous solution of cerium nitrate concentration of 28 wt.%, 205,4 g of an aqueous solution of oxynitride zirconium concentration of 18 wt.%, of 2.18 g of praseodymium nitrate, 2,89 g lanthanum nitrate and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon) was dissolved in 2 liters of water purified by ion exchange, and added an aqueous solution of ammonia concentration of 25 wt.% in an amount corresponding to 1.2-fold excess of cations, after which the precipitate obtained by coprecipitation, was filtered and washed to obtain the precursor medium. Then the predecessor of the carrier was dried at 110°C and then progulivali at 1000°C for 5 hours in air to obtain the carrier with the structure of calcium fluoride containing complex oxide of cerium-zirconium-praseodymium-lanthanum (mixing ratio: 53 mol.% CeO2, 45 mol.% ZrO2and 0.5 mol.% Pr2O3and 0.5 mol.% La2O3the number M of the metal element with respect to the number of media (calculated as metal): 55 the ol.%). In addition, the lattice constant in the resulting media was 5,304 Å.

Then the media was fixated noble metal, to obtain a catalyst for purification of exhaust gases according to this invention. In other words, a mixed solution prepared by mixing 0.625 g of an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), with 200 ml of water purified by ion exchange was added 25 g of the carrier obtained as described above, to perform the impregnation and consolidation of platinum, and then the resulting material was progulivali at 500°C for 3 hours in air to obtain a catalyst for purification of exhaust gases (Pt (0.1 g)/CeO2-ZrO2-Pr2O3La2O3(100 g)) according to this invention.

Example 29

First of all, have produced a complex oxide of cerium-zirconium-praseodymium-yttrium (CeO2-ZrO2-Pr2O3- Y2O3) as a carrier. In other words, first 218,1 g of an aqueous solution of cerium nitrate concentration of 28 wt.%, 201,7 g of an aqueous solution of oxynitride zirconium concentration of 18 wt.%, 2,19 g of praseodymium nitrate, 5,13 g of yttrium nitrate and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon) was dissolved in 2 liters of water purified by ion exchange, and add the Yali aqueous ammonia concentration of 25 wt.% in number, corresponding to 1.2-fold excess of cations, after which the precipitate obtained by coprecipitation, was filtered and washed to obtain the precursor medium. Then the predecessor of the carrier was dried at 110°C and then progulivali at 1000°C for 5 hours in air to obtain the carrier with the structure of calcium fluoride containing complex oxide of cerium-zirconium-praseodymium-yttrium (mixing ratio: 53 mol.% CeO2, 44 mol.% ZrO2and 0.5 mol.% Pr2O3, 1 mol.% Y2O3the number M of the metal element with respect to the number of media (calculated as metal): 56 mol.%). In addition, the lattice constant in the resulting media was 5,304 Å.

Then the media was fixated noble metal, to obtain a catalyst for purification of exhaust gases according to this invention. In other words, a mixed solution prepared by mixing 1,563 g of an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), with 200 ml of water purified by ion exchange was added 25 g of the carrier obtained as described above, to perform the impregnation and consolidation of platinum, and then the resulting material was progulivali at 500°C for 3 hours in air to obtain a catalyst for purification of exhaust gases (Pt (0.25 g)/CeO2-ZO 2-Pr2O3-Y2O3(100 g)) according to this invention.

Example 30

First of all produced a complex oxide of cerium-zirconium (CeO2-ZrO2) as a carrier. In other words, first 273,3 g of an aqueous solution of cerium nitrate concentration of 28 wt.%, 130,4 g of an aqueous solution of oxynitride zirconium concentration of 18 wt.% and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon) was dissolved in 2 liters of water purified by ion exchange, and added an aqueous solution of ammonia concentration of 25 wt.% in an amount corresponding to 1.2-fold excess of cations, after which the precipitate obtained by coprecipitation, was filtered and washed to obtain the precursor medium. Then the predecessor of the carrier was dried at 110°C and then progulivali at 1000°C for 5 hours in air to obtain the carrier with the structure of calcium fluoride containing complex oxide of cerium-zirconium (mixing ratio: 70 mol.% CeO2, 30 mol.% ZrO2the number M of the metal element with respect to the number of media (calculated as metal): 70 mol.%). In addition, the lattice constant in the resulting media was 5,334 Å.

Then the media was fixated noble metal, to obtain a catalyst for the purification o opnah gases according to this invention. In other words, a mixed solution prepared by mixing 1,563 g of an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), with 200 ml of water purified by ion exchange was added 25 g of the carrier obtained as described above, to perform the impregnation and consolidation of platinum, and then the resulting material was progulivali at 500°C for 3 hours in air to obtain a catalyst for purification of exhaust gases (Pt (0.25 g)/CeO2-ZrO2(100 g)) according to this invention.

Example 31

First of all produced a complex oxide of cerium-zirconium-yttrium (CeO2-ZrO2-Y2O3) as a carrier. In other words, first 242,6 g of an aqueous solution of cerium nitrate concentration of 28 wt.%, 157,6 g of an aqueous solution of oxynitride zirconium concentration of 18 wt.%, of 12.6 g of yttrium nitrate and 10 g of nonionic surfactant (available on the market by Lion Corporation, trade name: Leocon) was dissolved in 2 liters of water purified by ion exchange, and added an aqueous solution of ammonia concentration of 25 wt.% in an amount corresponding to 1.2-fold excess of cations, after which the precipitate obtained by coprecipitation, was filtered and washed to obtain the precursor medium. Then the predecessor of the carrier was dried at 110°C and p is after this was progulivali at 1000°C for 5 hours in air, to get the carrier with the structure of calcium fluoride containing complex oxide of cerium-zirconium-yttrium (mixing ratio: 60 mol.% CeO2, 35 mol.% ZrO2and 2.5 mol.% Y2O3the number M of the metal element with respect to the number of media (calculated as metal): 65 mol.%). In addition, the lattice constant in the resulting media was 5,305 Å.

Then the media was fixated noble metal, to obtain a catalyst for purification of exhaust gases according to this invention. In other words, a mixed solution prepared by mixing 0,169 g of barium nitrate with 200 ml of water purified by ion exchange was added 25 g of the carrier obtained as described above, to perform the impregnation and consolidation, after which the resulting material was progulivali at 500°C for 5 hours in air to obtain a catalyst precursor. Then, to the mixed solution prepared by mixing 1,563 g of an aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), with 200 ml of water purified by ion exchange was added 25 g of the carrier obtained as described above, to perform the impregnation and consolidation of platinum, and then the resulting material was progulivali at 500°C for 3 hours in air to obtain a catalyst for purification of exhaust gases (Pt (0.5 g)/CeO 2-ZrO2-Y2O3-BaO (100 g)) according to this invention.

Example 32

The catalyst for purification of exhaust gases (Pt (0.5 g)/CeO2-ZrO2-Y2O3-BaO (100 g)) according to this invention were prepared in the same manner as in Example 31, except that the amount of nitrate of barium, which was mixed with the mixed solution was changed to 0,338,

Example 33

The catalyst for purification of exhaust gases (Pt (0.5 g)/CeO2-ZrO2- Pr2O3La2O3(100 g)) according to this invention were prepared in the same manner as in Example 28, except that the amount of aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), which was mixed with the mixed solution was changed to 3,125,

Example 34

The catalyst for purification of exhaust gases (Pt (1 g)/CeO2-ZrO2-Pr2O3La2O3(100 g)) according to this invention were prepared in the same manner as in Example 28, except that the amount of aqueous solution dinitrodiphenylamine, acidified with nitric acid (concentration of platinum: 4 mass%), which was mixed with the mixed solution was changed to 6.25,

Example 35

The catalyst for purification of exhaust gases (Pt (0.25 g)/CeO2-ZrO2(100 g)) according to this invention privotal the Wali in the same way, as in Example 30, except that didn't add nonionic surfactant.

<Test the durability of A (1000°C)>

Life test in enriched/depleted atmosphere, simulating the functioning of the three-component catalyst, carried out using the catalysts for purification of exhaust gases, prepared according to Examples 28 through 30 and 34, 35. In other words, first of all, each catalyst was ground to obtain a particle size of from 0.5 to 1 mm when using cold isostatic molding (CIP) at a pressure of 1 t/cm2to obtain a granular catalyst. Then the enriched gas (CO (3,75% by volume)/H2(to 1.25% by volume)/H2O (3% by volume)/N2(rest) and depleted gas (O2(5% by volume)/H2O (3% by volume)/N2(else) at a flow rate of 333 cm3/min to 1.5 g of the resulting pelletized catalyst is alternately passed (in a simulated gas atmosphere) every 5 minutes and fixed at a temperature of 1000°C for 5 hours (life test A). It was estimated specific surface area and average particle diameter of the noble metal after such life tests; the results are presented in table 10. In addition, the estimated average diameter of h is STIC noble metal after such tests on the durability of the way chemisorption of CO, described in JP 2004-340637 A.

In addition, the ratio (V/X) the number of Pt (V), mounted on the carrier, and the standard value X is calculated according to equation (4):

X = (σ/100) · S/S · N · Mnm· 100 (4)

where σ, S, s, N and Mnmdefined in equation (1), obtained using the values of the specific surface area after such tests on durability. The results are presented in table 10. Moreover, the ratio (V/X) of the quantities fixed Pt (V) and the standard value X obtained by calculating according to equation (4) for catalyst for purification of exhaust gases (Examples 28 through 30) according to this invention were respectively about 0,59 (Example 28), approximately 1,23 (Example 29) and about 0,51 (Example 30). On the other hand, the ratio (V/X) for a catalyst for purification of exhaust gases (Examples 34 and 35) were respectively about 5,58 (Example 34) and approximately 7,50 (Example 35).

<evaluation of the activity of the three-component catalytic Converter>

By using each of the catalysts for purification of exhaust gases, prepared according to Examples 28, 30, 34 and 35 (the original) and catalysts for purification of exhaust gases according to Examples 28, 30, 34 and 35 after life tests A, AC gaseous environment were prepared using CO (75% by volume)/H2(25%) Il the O 2(100% by volume) for the stoichiometric model of the gas atmosphere, are presented in table 9, so that λ = 1±0,02 (2), missed per 1 g of the catalyst at a flow rate of 3.5 l/min and the catalyst was subjected to treatment at 550°C for 10 minutes, performed after increasing the temperature at a rate of 12°C/min from 100°C to 550°C to determine the temperature of the cleaning by 50% for each component. The cleaning temperature by 50 % for propylene (C3H6) are presented in table 10. In addition, the cleaning temperature by 50% for propylene (C3H6), are presented in table 10, is a measure of performance of three-component catalytic Converter and means that the lower the temperature, the higher the catalyst activity.

Moreover, on the basis of the catalyst for purification of exhaust gases, prepared according to Example 28 (initial)compared the amount of adsorbed CO in the calculation of the amount of Pt after testing the durability of A (measurement of the specific activity). The results are presented in table 10. In addition, the value of the specific activity obtained in this way indicates a higher activity compared with the activity of the catalyst (original)prepared according to Example 28, since this value is greater than 1; when the value is close to the 1, this indicates that the activity of the catalyst prepared according to Example 28 (initial), closer to the activity of the catalyst (original)prepared according to Example 28, in the calculation of the amount of Pt; and indicates that reducing the value to 1 activity per amount of Pt is lower than the activity of the catalyst (original)prepared according to Example 28.

Table 9
Vol.%
CO(75%)/H2CO2O2NOC3H6H2ON2
0,699880,6460,120,165rest

The results verify the operation of the three-component catalytic converters (temperature 50% purification of propylene) after testing the durability of each of the catalysts for purification of exhaust gases, prepared according to Examples 28 and 34, which are shown in table 10, p is led, the catalyst prepared according to Example 34, with the number of Pt mounted on the carrier 10 times the number of Pt enshrined in the catalyst prepared according to Example 28 shows a higher activity. However, the specific activity of the catalyst prepared according to Example 34, after testing the durability is reduced to 0.04, while in the case of the catalyst prepared according to Example 28, even after life tests is assigned a high value of specific activity, component of 0.85. These results confirm that the deterioration of the catalyst may be hindered significantly. As expected, this is due to the following. Namely, in the catalyst for purification of exhaust gases, prepared according to Example 28, the difference in activity before testing the durability and after them a little, because on the surface of the carrier there is a sufficient number of places for fixing of the atoms of the noble metal, which is a consequence of the growth of the grains of Pt. On the other hand, in the catalyst for purification of exhaust gases, prepared according to Example 34, there is a marked decrease in catalytic activity as compared to the initial value, due to the excessively increased grain size Pt after life tests.

Furthermore, cf is the ranking of the characteristics of three-component catalytic Converter (temperature 50% purification of propylene) in the case of the catalysts for purification of exhaust gases, prepared according to Examples 30 and 35, after life tests shows that, although there is the same amount of Pt and the medium has the same composition, for these two catalysts, the temperature difference of 50% purification of propylene is almost 100°C. These results are believed to be explained by the fact that the medium used for catalyst for purification of exhaust gases, prepared according to Example 35, has insufficient surface area, even if he has the same composition as the medium used for catalyst for purification of exhaust gases, prepared according to Example 29, and accordingly does not have enough seats to secure a sufficient number of atoms of the noble metal on the surface of the carrier and is not able to retain the noble metal in a highly dispersed state.

<life Test B (950°C)>

Life test in enriched/depleted atmosphere, simulating the functioning of the three-component catalyst, carried out using the catalysts for purification of exhaust gases, prepared according to Examples 28, 29 and 31 to 34. In other words, first of all, each catalyst was ground to obtain a particle size of from 0.5 mm to 1 mm when using cold isostatic molding (CIP pic is b) at a pressure of 1 t/cm 2to obtain a granular catalyst. Then the enriched gas (CO (5% by volume)/CO2(10% by volume)/H2O (3% by volume)/N2(rest) and depleted gas (O2(5% by volume)/CO2(10% by volume)/H2O (3% by volume)/N2(else) at a flow rate of 500 cm3/min to 3 g of the resulting pelletized catalyst is alternately passed (in a simulated gas atmosphere) every 5 minutes and fixed at a temperature of 950°C for 5 hours (endurance testing).

It was estimated specific surface area of each catalyst and the average particle diameter of the noble metal after such life tests; the results are presented in table 11. When this average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A.

<Conditions of regeneration>

0.7 g of each of the catalysts for purification of exhaust gases, prepared according to Examples 28, 29 and 31 to 34 after life tests B, was subjected to oxidation treatment (the process of re-dispersion) at 800°C for 15 minutes in an atmosphere in which a gas containing O2(20%)/He (80% by volume), proceeded with a flow rate of 150 ml/min for 0.7 g of the catalyst, to try and re-dispersing the noble metal. The average particle diameter of blagorodnometal in the catalysts for purification of exhaust gases after such a process of re-dispersion is presented in table 11. The average particle diameter of the noble metal was estimated by the method of CO chemisorption described in JP 2004-340637 A. Such a re-dispersion and restoration pre-treatment, in accordance with the results of measurements by the method of CO chemisorption, achieved oxidative and reductive treatments of each of the catalyst for purification of exhaust gases that make up the process of regeneration.

Table 11
The specific surface of the carrier (m2/g)The amount of Pt per 100 g of carrier (g)The proportion of the number of assigned Pt (V/X)The way chemisorption COSpecific activity
The diameter of the Pt particles (nm)The degree of dispersion (%)
Example 28Original0,10,8359,11,00
After testing, the durable to u is ity B 24,60,390,9452,10,88
After the regeneration process24,60,8856,50,96
Example 29Original0,250,85of 57.50,97
After life tests B24,20,824,0012,30,21
After the regeneration process24,21,7029,70,50
Example 31Original0,50,770,9352,90,90
P the following tests on the durability B 20,62,3121,30,36
After the regeneration process20,61,7627,60,47
Example 32Original0,50,9551,50,87
After life tests B15,11,051,9325,40,43
After the regeneration process15,11,7428,20,48
Example 33Original0,50,8557,40,97
Last the tests of durability B to 25.31,884,84the 10.10,17
After the regeneration processto 25.32,1023,00,39
Example 34Original10,8856,10,95
After life tests B19,1equal to 4.978,795,60,09
After the regeneration process19,13,9712,40,21

As can be seen from the results shown in table 11 confirms that the grain growth of Pt after life tests in the catalysts for purification of exhaust gases, prepared according to Examples 28, 29 and 31 to 33, is restrained. In addition, it is confirmed that in the catalysts for purification of exhaust g the call, prepared according to Examples 28, 29 and 31 to 33, the activity unit quantity Pt (specific activity) high and is at 1.17 or more even after life tests, and, in addition, the regeneration process provides a significant decrease in the diameter of the Pt particles, restoring specific activity to a value of about 0.4. On the other hand, is confirmed by what happens grain growth of the noble metal, and its specific activity is decreased to 0.1 or less in the catalyst for purification of exhaust gases, prepared according to Example 34. In addition, it is confirmed that the specific activity does not improve significantly even when using the process of regeneration of the catalyst.

In addition, it is confirmed that in the catalysts for purification of exhaust gases, prepared according to Examples 31 and 32, which are received by the consolidation of barium, which is the alkaline earth metal on the surface of the carrier and the subsequent fastening of the noble metal is additionally constrained by the grain growth of Pt. This result is believed due to the improvement of basicity of the medium by adding barium. In addition, the ratio of Pt (V)attached to the carrier, and the standard value X in table 11 calculated by the equation (4), is small compared to the actual is some value since this ratio is calculated under the assumption that the amount of barium mounted on the carrier, evenly distributed throughout the volume. In addition, for a catalyst for purification of exhaust gases, prepared according to Example 33, confirmed that the grain growth of Pt is constrained and that the regeneration process provides a significant decrease in the diameter of the Pt particles, restoring their specific activity. Confirmed that these effects are also visible in the catalysts for purification of exhaust gases, prepared according to Examples 31 and 32.

Applicability in industrial conditions

As described above, in accordance with this invention, may provide a catalyst for purification of exhaust gases, which can sufficiently be restrained aggregation of particles of the noble metal, in order largely to prevent grain growth of the noble metal, even if they are exposed to exhaust gases at a high temperature for a long period of time, whereby the catalyst enables a sufficient deterrent reduction of catalytic activity and the possibility of re-dispersion of the particles of the noble metal in a short time, so a simple way to restore catalytic activity, when the origin Taiwan is the CIO grain growth using a catalyst, even if the particles of the noble metal are in an area with a relatively low temperature, and also allows regeneration of the catalyst is simple, even in a state in which it is installed in the exhaust system of the internal combustion engine, method of regeneration of this catalyst for purification of exhaust gases, as well as devices for purifying exhaust gas and method for purification of exhaust gases by using this catalyst for purification of exhaust gases.

Accordingly, this invention is applicable is extremely advantageous way as a technology for the use of the catalyst for purification of exhaust gas to remove harmful components such as HC, CO and NOxin the exhaust gases of automobile engines for a long period of time without deterioration of catalytic activity.

1. The catalyst for purification of exhaust gases, in which a noble metal is fixed on a metal oxide carrier, while
the carrier contains a complex oxide of Zirconia and/or alumina and at least one element selected from the group consisting of alkaline earth elements, rare earth elements and group 3A
an additional component attached to the carrier and containing at least one element selected from the gr is PPI, consisting of alkaline earth elements, rare earth elements and group 3A
the amount of noble metal attached to the carrier is in the range from 0.05 to 2% by weight of the weight of the catalyst, and the molar ratio (the number of additional component/amount of precious metal) the amount of additional component attached to the carrier, and the amount of the noble metal is in the range from 0.5 to 20 per metal,
in an oxidizing atmosphere the precious metal is on the surface of the medium in a condition of high degree of oxidation, and this noble metal is associated with the cation of the media via an oxygen atom on the surface of the carrier, to form a surface oxide layer, and
in a reducing atmosphere, a noble metal is on the surface of the carrier in the metallic state, and the amount of noble metal, open at the surface of the carrier measured by chemisorption of CO, 10% or more per atomic proportion in relation to the total amount of the noble metal attached to the media.

2. The catalyst for purification of exhaust gases according to claim 1, in which
the noble metal is at least one element selected from the group consisting of platinum, palladium and rhodium.

3. The catalyst is La purification of exhaust gases according to claim 1, in which
the magnitude of the binding energy of the orbitals Is oxygen atom in the media is 531 eV or less.

4. The catalyst for purification of exhaust gases according to claim 1, in which
the electronegativity of at least one cation among cations in the media less electronegativity of Zirconia.

5. The catalyst for purification of exhaust gases according to claim 1, in which
the molar ratio of the cation and the noble metal (cation/noble metal) is 1.5 or more, this cation is open on the surface of the carrier and has an electronegativity less electronegativity of Zirconia.

6. The catalyst for purification of exhaust gases according to claim 1, in which
the carrier contains a complex oxide of Zirconia and/or alumina and at least one element selected from the group consisting of magnesium, calcium, barium, lanthanum, cerium, neodymium, praseodymium, yttrium and scandium.

7. The catalyst for purification of exhaust gases according to claim 1, in which
an additional component contains at least one element selected from the group consisting of magnesium, calcium, neodymium, praseodymium, barium, lanthanum, cerium, yttrium and scandium.

8. The catalyst for purification of exhaust gases according to claim 1, also containing iron, fixed media, in which
the molar ratio (the amount of iron/number of precious metal) the quantity W is found mounted on the carrier, and the amount of the noble metal is in the range from 0.8 to 12 per metal.

9. The catalyst for purification of exhaust gases according to claim 1, in which
the carrier is the carrier with the fluorite structure containing complex oxide of zirconium and at least one metallic element comprising cerium and selected from the group consisting of rare earth elements and alkaline earth elements; and
the amount of the metal contained in the carrier is in the range from 51 to 75 mol.% in the calculation of the metal in relation to the number of the carrier; the number of cerium among other metal elements is 90 mol.% or more per metal relative to the total amount of metal elements; and the amount of noble metal, mounted on 100 g of the carrier, two times or less larger than the standard value X is in the range from 0.01 to 0.8 g, with a standard value X is calculated according to equation (1):

where X is a standard value (unit: g) of the amount of precious metal to 100 g of the carrier; and σ represents the probability (unit: %), with which the metallic element is surrounded by a metal element, the probability of σ is calculated in accordance with equation (2):
where M represents the share (unit: mol.%) the metal element contained in the media; S is the specific surface area (unit: m2/g) media; s represents a single area (unit:2/number one cation, this single area s is calculated by the equation (3):

where a represents the lattice constant (unit: N is the Avogadro's number (of 6.02·1023(unit: number); and Mnmrepresents an atomic mass of noble metal attached to the media.

10. Method for regenerating catalyst for purification of exhaust gases, in which
the catalyst for purification of exhaust gases according to any one of claims 1 to 9 is applied oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and restorative treatment.

11. The regeneration method of claim 10, in which
the temperature during the oxidation treatment is from 500 to 1000°C.

12. The regeneration method of claim 10, in which
the oxygen concentration in the oxidizing atmosphere is 1% by volume or more.

13. The regeneration method of claim 10, in which the oxidation treatment and reducing treatment is performed in a state in which a catalyst for purifying you lobnig gases installed in the exhaust system of the internal combustion engine.

14. The regeneration method of claim 10, including:
step of installing a temperature sensor in the catalyst for purification of exhaust gases and determining the degree of degradation of the catalyst for purification of exhaust gases based on the time of operation and temperature defined by the temperature sensor; and
the stage of initiation of the regeneration process after determining the location of the catalyst in a state of degraded performance.

15. The regeneration method of claim 10, including:
the stage of determining the state of the degraded catalyst for purification of exhaust gas using the device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases; and
the stage of initiation of the regeneration process after determining the location of the catalyst in a state of degraded performance.

16. Device for purification of exhaust gases containing:
a pipe for supplying exhaust gases
the catalyst for purification of exhaust gases according to any one of claims 1 to 9, the catalyst is placed inside the pipe for supplying exhaust gas temperature sensor installed in the catalyst for purification of exhaust gases, and
a control unit for determining the degree of deterioration of the characteristics of a cat who lyst for purification of exhaust gases based on the time of operation and temperature, a thermal sensor, and the initiation of the regeneration process using the catalyst oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and the recovery processing after it is determined that the catalyst is in a state of degraded performance.

17. Device for purification of exhaust gases containing:
a pipe for supplying exhaust gases
the catalyst for purification of exhaust gases according to any one of claims 1 to 9, the catalyst is placed inside the pipe for supplying exhaust gases
device for diagnosing deterioration of characteristics of the catalyst, which determines the state of degradation of the catalyst for purification of exhaust gases, and
the control unit, which initiates the regeneration process using the catalyst oxidation treatment by heating in an oxidizing atmosphere containing oxygen, and the recovery processing after it is determined that the catalyst is in a state of degraded through the device for diagnosing deterioration of characteristics of the catalyst.

18. Method for purification of exhaust gases, including
purification of exhaust gas by bringing the exhaust gas into contact with the catalyst for purification of exhaust gases according to any one of claims 1 to 9.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method of decomposing nitrogen dioxide (NO2) to nitrogen monoxide (NO) in the exhaust gas of an internal combustion engine working on a rare fuel mixture involves a stage for bringing into contact with an acidic metal oxide selected from a group consisting of zeolites, titanium dioxide doped with tungsten, silica-titanium dioxide, zirconium dioxide-titanium dioxide, gamma-alumina, amorphous silica-alumina and a mixture of any two or more of these oxides, which optionally serve as a carrier for metal or metal compound, where the metal is selected from a group consisting of rhodium, palladium, iron, copper and mixtures of any two or more metals, with a gaseous mixture containing exhaust gas, control of composition of the gaseous mixture, injection of hydrocarbons into the gaseous mixture at a rate which varies during the operation cycle such that on average, the ratio Cl hydrocarbon: nitrogen oxides (CI HC:NOx) of the gaseous mixture in contact with the acidic metal oxide ranges from 0.1 to 1.5 and release of the exhaust gas directly into the atmosphere, optionally after the gaseous mixture comes into contact with a hydrocarbon oxidation catalyst, where the hydrocarbons are selected from a group consisting of diesel fuel, petrol, fuel based on liquefied gas and liquefied petroleum gas. The exhaust system for the internal combustion engine working on a rare fuel mixture, which contains a catalyst for decomposition of nitrogen dioxide (NO2) to nitrogen monoxide (NO) with a hydrocarbon as a reducing agent, and apparatus for controlling composition of the exhaust gas by injecting a hydrocarbon at a rate which varies during the operation cycle such that on average, the ratio Cl hydrocarbon: nitrogen oxides (CI HC:NOx) in the exhaust gas in contact with the catalyst ranges from 0.1 to 1.5, in which the catalyst consists of an acidic metal oxide selected from a group consisting of zeolites, titanium dioxide doped with tungsten, silica-titanium dioxide, zirconium dioxide-titanium dioxide, gamma-alumina, amorphous silica-alumina and a mixture of any two or more oxides, which optionally serve as a carrier for the metal or metal compound. The metal is selected from a group consisting of rhodium, palladium, iron, copper and mixtures of any two or more metals, in which gas released from the catalyst is directly released into the atmosphere optionally through a hydrocarbon oxidation catalyst. Hydrocarbons are selected from a group consisting diesel fuel, petrol, fuel based on liquefied gas and liquid petroleum gas. The device has a diesel engine and the above described exhaust system features. A carriage vehicle, such as one used in mines, has the above described device.

EFFECT: invention reduces exhaust gas emissions into the atmosphere in confined spaces in order to improve health and safety of miners.

41 cl, 1 dwg

FIELD: engines and pumps.

SUBSTANCE: proposed ICE exhaust gas purifier is designed as SOx catalyst-trap to entrap sulphur oxides of exhaust gases in the engine exhaust pipe. One of alkaline and alkali-earth metals is diffused into catalyst-trap. In engine operation, keeping the SOx catalyst-trap temperature, whereat nitrate of at least one of alkaline and alkali-earth metals changes into molten state, stimulates nitrate displacement and its coagulation effect. Note here that nitrate in SOx catalyst-trap displaces and coagulates on SOx catalyst-trap surface to remove SOx, and, at the same time, to recover the degree of SOx entrapping.

EFFECT: higher degree of SOx entrapping.

24 cl, 23 dwg

FIELD: automotive industry.

SUBSTANCE: invention relates to automotive industry. Proposed device comprises controller to shift automatic gearbox completely in neutral. Proposed method consists in that forced gearbox shifting in neutral is carried out provided preset conditions are satisfied. Note here that said conditions comprise verifying automatic gearbox completely automatic gearshift position. Catalytic neutraliser temperature is increased when amount of exhaust particles accumulated in catalytic neutraliser exceeds first threshold value. If, in regulation of catalytic neutraliser heating, the amount of exhaust particles accumulated in said neutraliser exceeds second threshold value, forced shifting of automatic gearbox into completely neutral is inhibited.

EFFECT: recovery of efficient operation of catalytic neutraliser and fuel saving.

14 cl, 2 dwg

FIELD: engines and pumps.

SUBSTANCE: invention can be used in ICE exhaust systems. Proposed assembly serves to admix liquid reducer into waste gas flow and comprises proportioning pump (2). Inlet of aforesaid pump is furnished with element connecting it to reducer tank (4), while pump outlet is connected with pressure line (16). Return line (10) connects pump outlet with aforesaid reducer tank (4). Pressure tank (16) accommodates check valve (20) to response to fluid medium pressure generated by proportioning pump (2). Return line (10) communicates with pressure line (16) and accommodates shut-off valve (12) to shut off return line selectively.

EFFECT: simplified design.

13 cl, 7 dwg

FIELD: engines and pumps.

SUBSTANCE: Mixing device preferably comprises inlet urea channel and inlet gas channel for supply of accordingly urea and gas into mixing chamber of mixing device and outlet channel for discharge of urea and gas mixture from mixing chamber, at that these inlet channels and outlet channel may preferably be extended to the side of flow and preferably pass into mixing chamber, and outlet channel preferably starts from mixing chamber. Device comprises valve in inlet channel that provides for removal of crystals on channel surfaces, at that valve is arranged with the possibility to execute reciprocal motion. Valve comprises piston with spring facility and flat element with opening.

EFFECT: such arrangement reduces deposit of urea crystals on surfaces of inlet channel.

22 cl, 16 dwg

FIELD: machine building.

SUBSTANCE: proposed inventions can be used in exhaust systems and covers the method and device to adjust adding reducer at the point upstream higher than that the catalyst is located in the ICE exhaust manifold at. In compliance with the proposed invention, the reducer addition into inlet pipeline is adjusted subject to the results of comparison between the actual calculated accumulated amount (A1) and calculated preset accumulated amount (A2). The invention covers also a computer hardware unit incorporating a data carrier adapted for reading off by an electronic control unit and store computer program therein designed to force the said control unit to realise aforesaid method.

EFFECT: efficient method and device to adjust adding reducer at point upstream higher than that catalyst is located in ICE exhaust manifold at.

25 cl, 9 dwg

FIELD: mechanical engineering; internal combustion engines.

SUBSTANCE: invention can be used in engine exhaust system. Proposed device for processing of exhaust gases by selective catalytic reduction of nitrogen oxides in exhaust gases formed when engine operates on lean mixtures includes at least one catalyst with catalytically active component for selective catalytic reduction (components for scr) and at least one accumulating component for nitrogen oxides (components for NO). Device contains also oxidizing catalyst arranged before selective catalytic reduction catalyst and accumulating component for nitrogen oxides is at least one compound of element chosen from row including alkaline metals, alkaline-earth metals and cerium. Method of removal of nitrogen oxides from exhaust gases is provided.

EFFECT: reduced concentration of nitrogen oxides in exhaust gases formed at operation on lean mixtures.

18 cl, 3 dwg

The invention relates to a device for catalytic reduction of nitrogen oxides contained in the exhaust gases (EXHAUST gas) internal combustion engine

The invention relates to a method and apparatus for neutralizing containing oxides of nitrogen (NOx) exhaust gases of the internal combustion engine (ice) having at least one combustion chamber connected to the exhaust pipe connected to the exhaust line to the exhaust manifold and at least one catalytic Converter EXHAUST

The invention relates to a system for neutralization of exhaust gases of the internal combustion engine (ice) and the method of controlling the operation of such a system

FIELD: metallurgy.

SUBSTANCE: invention refers to particles of metal oxide carrier of catalyst, method of such particle obtainment, waste gas treatment catalyst including metal oxide catalyst, and method of waste gas treatment catalyst recovery. Invention describes particle of metal oxide catalyst carrier, consisting of central part and external shell part, where both central and external shell parts include first metal oxide and second metal oxide, central part and external shell part differ in composition, molar fraction of first metal oxide is higher in central part than in external shell part, molar fraction of second metal oxide is higher in external shell part than in central part, and first metal oxide is aluminium or zirconium oxide while second metal oxide is selected out of group including neodymium, praseodymium, lanthanum, scandium and yttrium oxides. Invention describes waste gas treatment catalyst including the claimed particle of metal oxide carrier and platinum applied onto the particle of metal oxide catalyst carrier. Invention describes method of waste gas treatment catalyst recovery involving waste gas treatment catalyst heating at 500°C or higher in oxidation medium including oxygen. Also invention describes method of obtaining particle of metal oxide catalyst carrier, consisting of central part and external shell part, where both parts include first metal oxide and second metal oxide, central part and external shell part differ in composition. Method involves obtainment of material solution including at least colloid particles of first metal oxide and metal salts of second metal oxide, where first metal oxide is aluminium or zirconium oxide, second metal oxide is selected out of group including neodymium, praseodymium, lanthanum, scandium and yttrium oxides; achievement of solution pH close to isoelectric point of colloid particles of first metal oxide so as to coagulate colloid particles of the first metal oxide; solution pH increase so as to cause precipitation of colloid particles of the second metal oxide from metal salts and coagulate colloid particles of the second metal oxide around coagulated colloid particles of the first metal oxide, where isoelectric point of colloid particles of the second metal oxide is higher than isoelectric point of colloid particles of the first metal oxide; and coagulated product drying and calcination.

EFFECT: increased specific area of waste gas treatment catalyst surface, increased degree of platinum particle recovery.

10 cl, 19 ex, 2 tbl, 3 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to methods of reducing platinum-rhenium reforming catalyst and can be used on oil-refining, petrochemical and gas production enterprises. A method is proposed for reducing platinum-rhenium reforming catalyst through high temperature treatment with a circulating reforming hydrogen-containing gas, containing an additive of sulphur compounds in amount of 0.05-0.30 % of the mass of catalyst (in terms of sulphur) in two stages. The method is distinguished by that, the platinum-rhenium catalyst is pre-treated only with hydrogen-containing gas at temperature 480-500°C for 2-4 hours, and treatment with sulphur compound additives at the first stage is done at temperature 480-400°C, and 280-260°C at the second stage.

EFFECT: significant increase of octane number of reformate, as well as inter-regeneration cycle of the catalyst.

4 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: method of regeneration of the palladium catalyst of the hydrogenation of acetylenic hydrocarbons is described by processing it using an inert gas, then by mixture of an inert gas with an oxygen-containing gas at raised temperature till the content of CO2 in the outgoing regeneration gas is less than 0,05 % vol., cooling of the catalyst, the subsequent restoration of the catalyst from the oxidized form of palladium up to metal in an atmosphere of hydrogen containing gas and its cooling up to the temperature of the reaction of hydrogenation, and the catalyst after inert-gas flushing, additionally blow hydrogen-containing gas at the temperature 200-250°C and regeneration of the catalyst layer in adiabatic reactor is conducted separately, with a separate supply and outlet of regeneration gas for each catalyst layer.

EFFECT: improvement of restoration of operational characteristics of the palladium catalyst at carrying out the of process of regeneration.

3 cl, 2 tbl, 6 ex

FIELD: methods of extraction and separation of platinum and rhenium in processing waste bimetallic reforming catalysts.

SUBSTANCE: proposed method includes alkali sintering and aqueous leaching-out for obtaining the solution containing sodium permeate and insoluble residue. Alkali sintering is carried out in presence of oxidant in form of agent generating the gaseous sulfur anhydride, sodium bisulfate or sodium permeate in particular. Insoluble residue is leached-out with hydrochloric acid for dissolving of platinum. Through extraction of rhenium and platinum into commercial product ranges from 96.6 to 99.2%, respectively. Proposed method requires no special equipment.

EFFECT: high degree of extraction of platinum and rhenium.

3 cl, 2 ex

FIELD: hydrogenation-dehydrogenation catalysts.

SUBSTANCE: invention provides catalytic composition for dehydration of alkylaromatic hydrocarbons optionally combined with ethane comprising: carrier consisting of alumina in δ phase or in θ phase, or in mixed δ+θ or θ+α, or δ+θ+α phase, modified with silicon oxide and having surface area less than 150 m2/g as measured by BET method; 0.1-35% gallium in the form of Ca2O3; 0.01-5% manganese in the form of Mn2O3; 0-100 ppm platinum; and 0.05-4% alkali or alkali-earth metal oxide, all percentages being based on the total weight of composition. Other variants of composition are also covered by invention. Methods of preparing such catalytic composition (options) envisage use of alumina-based carrier in the form of particles corresponding to group A of the Geldart Classification. Process of dehydration of alkylaromatic hydrocarbons optionally combined with ethane comprises: (i) dehydration of hydrocarbon stream optionally mixed with inert gas in fluidized-bed reactor in presence of catalytic composition consisted of alumina-supported and silica-modified gallium and manganese at temperature within a range of 400 to 700°C, total pressure within a range of 0.1 to 3 atmospheres, and gas hourly space velocity from 50 to 10000 h-1; and (ii) regeneration and heating of catalyst caused by catalytic oxidation of fuel in fluidized-bed reactor at temperature above 400°C.

EFFECT: increased activity of catalytic composition and prolonged lifetime thereof.

22 cl, 2 tbl, 16 ex

FIELD: inorganic synthesis catalysts.

SUBSTANCE: ammonia synthesis catalyst includes, as catalytically active metal, ruthenium deposited on magnesium oxide having specific surface area at least 40 m2/g, while concentration of ruthenium ranges between 3 and 20 wt % and content of promoter between 0.2 and 0.5 mole per 1 mole ruthenium, said promoter being selected from alkali metals, alkali-earth metals, lanthanides, and mixtures thereof. Regeneration of catalytic components from catalyst comprises following steps: (i) washing-out of promoters from catalyst thereby forming promoter-depleted catalyst and obtaining solution enriched with dissolved promoter hydroxides; (ii) dissolution of magnesium oxide from promoter-depleted catalyst in acidic solvent wherein ruthenium is insoluble and thereby obtaining residual ruthenium metal in solution enriched with dissolved magnesium compound; and (iii) regeneration of residual ruthenium metal from solution enriched with dissolved magnesium compound via liquid-solids separation to form indicated solution enriched with dissolved magnesium compound and ruthenium metal.

EFFECT: increased catalyst activity.

6 cl, 6 ex

FIELD: extraction of platinum and rhenium from decontaminated used platinum-rhenium catalysts; reworking of secondary raw materials of petrochemical industry.

SUBSTANCE: proposed method includes high-temperature oxidizing roasting at temperature of 1200-1300°C, wet trapping of rhenium by alkaline solution, leaching-out of cinder in hydrochloric acid solution at concentration of 100-150 g/dm3 in presence of oxidizing agent for setting the oxidizing-reducing potential of platinum electrode in pulp relative to saturated silver-chloride electrode equal to 850-1000 mV. Used as oxidizing agent is sodium hypochlorite or elementary chlorine or hydrogen peroxide.

EFFECT: enhanced efficiency of process.

1 tbl, 13 ex

FIELD: separation of palladium from waste mangani-palladium catalyst and cleaning of palladium.

SUBSTANCE: palladium-containing concentrate is treated with aqua regia solution and palladium is deposited in form of chloropalladate by means of treatment with aqua regia solution with solid ammonium chloride, pulp thus obtained is settled, cooled and filtered; sediment is treated with saturated hydrochloric acid solution of ammonium chloride. Then sediment thus treated is dissolved in water and solution is filtered and neutralized; pallarium is restored to metal by means of hydrochloric acid hydrazine at pH≥2 or formic acid solution at pH≥6; solution is filtered and metallic palladium is washed and dried at 90-100°C. Prior to treatment, mangani-palladium catalyst with aqua regia, it is dissolved in concentrated hydrochloric acid; solution is neutralized by asmmonia to pH=6-7 and treated with formic acid at flow rate no less than 1 l of HCOOH per kg of mangani-palladium catalyst; then mangani-palladium concentrate is filtered, washed and dried at 90-100ºC.

EFFECT: enhanced purity of metallic palladium at minimum losses of catalyst at all stages of chemical treatment.

4 ex

FIELD: noble metal hydrometallurgy.

SUBSTANCE: invention relates to method for acid leaching of platinum method from secondary raw materials, in particular from ceramic support coated with platinum metal film. Target metals are leached with mixture of hydrochloric acid and alkali hypochlorite at mass ratio of OCl-/HCL = 0.22-0.25 and redox potential of 1350-1420 mV.

EFFECT: decreased leaching temperature, reduced cost, improved platinum metal yield.

2 ex

The invention relates to the chemical industry, in particular to methods of regeneration of silver catalysts for the preparation of formaldehyde from methanol

FIELD: chemistry.

SUBSTANCE: invention relates to protection of the environment from toxic components of exhaust gases, and specifically to catalytic oxidation treatment of exhaust gases which contain hydrocarbons. The proposed catalyst which contains a noble metal and oxidised stainless steel also contains rhenium in amount of 0.05-0.25 wt % combined with platinum or palladium in the same concentration interval, and oxidised stainless steel constituting the remaining percentage. Reduction of platinum or palladium and rhenium with ammonia takes place at high temperature with their reaction with precursor compounds in accordance with the chemical equation: 3[Pt(NH3)4]Cl2+6NH4ReO4+6KOH→3Pt°+6Re°+8N2↑+2NH3↑+6KCl+30H2O.

EFFECT: given catalyst provides for high degree of purity at low temperatures, high thermal conductivity and mechanical strength at low cost.

4 tbl

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