Catalytic neutralizer and method of production of such neutralizer (versions)

FIELD: production of catalytic neutralizers.

SUBSTANCE: high-efficiency catalytic neutralizer has internal and external layers on inert carrier which contain noble metals of platinum group deposited on materials of base and oxygen-accumulating components. Inner layer of proposed catalytic neutralizer contains platinum deposited on first base and first oxygen-accumulating component and its external layer contains platinum and rhodium deposited on second base only; this second layer contains additionally second oxygen-accumulating component. Production of catalytic neutralizer includes application of coat on carrier made from composition containing powder-like materials including first material of base and first oxygen-accumulating component followed by drying, calcining, immersing the carrier with coat in solution of platinum precursor; coat is calcined and external layer is applied over previous layer. Specification describes two more versions of production of catalytic neutralizer.

EFFECT: enhanced ability of catalytic neutralizer for reduction of catalytic activity after aging due to discontinuation of delivery of fuel.

24 cl, 1 dwg, 11 tbl, 5 ex, 3 ex

 

The present invention relates to a highly efficient three-component catalytic Converter (TAC), comprising inner and outer layers on an inert carrier. These layers contain noble metals of the platinum group deposited on a material basis.

Three-way catalytic converters are used mainly for conversion contained in such exhaust gases (EXHAUST gas) internal combustion engines toxic constituents as carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx), into harmless substances. In the known three-component catalytic converters with high activity and durability by using one or more catalytic components of the platinum group metals such as platinum, palladium, rhodium and iridium deposited on a refractory oxide carrier with a large specific surface area, such as aluminum oxide with a large specific surface area. The basis is usually in the form of a thin layer or coating on acceptable carrier or substrate, such as a monolithic carrier, representing a refractory ceramic or metal honeycomb structure.

Growing demand for high catalytic activity and durability has led to the creation of complex catalytic forms, including many to naliticheskoj layers on the object structures, such as layers comprising materials selected fundamentals and catalytic components, as well as the so-called promoters, stabilizers and accumulate oxygen connection.

In the patent US 5063192 described three-way catalytic Converter with improved resistance to thermal stress, which has first and second catalytic layers. The first layer is applied as a coating directly on the surface of the monolithic honeycomb carrier and includes an active aluminum oxide and deposited on the catalytic components containing platinum and/or rhodium, and at least one compound from the group of zirconium oxide, lanthanum oxide or barium oxide. The second layer in the form of a coating applied over the first layer and comprises active alumina, cerium oxide and a catalytic component, which contains palladium. The oxides of zirconium, lanthanum and/or barium prevent sintering of the particles of active aluminum oxide due to the high temperatures of the EXHAUST gas and thereby increase the resistance of such a three-component catalytic Converter.

In the patent US 5677258 described three-component catalyst comprising an oxide of barium, with high resistance to poisoning by sulfur and water. This catalyst consists of two layers on a cellular carrier. The lower catalytic layer is located directly on the Le and includes at least barium or lanthanum. The top layer includes a water-absorbing component. The catalyst further includes a catalytically active metal, which is at least on the lower or upper layer. In a particular embodiment, the bottom layer further includes palladium and active aluminum oxide, and the upper layer further includes platinum and rhodium.

In the patent US 5057483 described three-way catalytic Converter, comprising two separate layers on a monolithic carrier. First, the lower layer includes a first activated aluminiumoxide media, a catalytically effective amount of a first platinum catalytic component dispersed on the first aluminiumoxide carrier and a catalytically effective amount of bulk cerium oxide. The second or outer layer includes a medium of conjunction of the obtained rare earth element oxide - zirconium dioxide, a catalytically effective amount of the first rhodium catalytic component dispersed on the carrier together from the obtained rare earth element oxide is Zirconia, the second media type aluminiumoxide carrier and a catalytically effective amount of a second platinum catalytic component dispersed on the second aluminiumoxide media.

In WO 95/35152 described another Tr is componentry catalytic Converter, comprising two layers which are thermally stable up to 900°C and above. The first layer includes the first carrier, at least one first palladium component, an optional first component element of the platinum group, at least one optional first stabilizer, at least one optional first component with a rare earth metal, and optionally a compound of zirconium. The second layer includes a second carrier, the second platinum component, a rhodium component, a second nakaplivalsya oxygen composition comprising a diluted second accumulating oxygen component, and optionally a zirconium component.

In DE 19726322-A1 describes a three-component catalytic Converter, which is characterized by high activity and thermal stability and which consists of two layers on an inert carrier. The first or bottom layer consists of several powdery materials, one or more highly dispersed oxides of alkaline earth metals and at least one platinum group metal, which is tightly in contact with all of the components of the first layer. Powdered materials of the first layer include at least one powder accumulating oxygen material and at least one additional powder component. The second layer also includes the t several powdery material and at least one platinum group metal. Powdered materials of the second layer include at least one powder accumulating oxygen material and additional powder component. The platinum group metals that of the second layer selectively precipitated powdery materials of the second layer. In a preferred embodiment, the platinum group metal in the first layer is palladium, and platinum group metals of the second layer consists of platinum and rhodium.

This last three-way catalytic Converter has an extremely high catalytic activity, especially in the phase of cold start of modern internal combustion engines, which during the cold start work on a lean air-fuel mixtures in order to rapidly increase the temperature of the EXHAUST gas. This extremely effective characterization of the catalytic Converter caused essentially by the use of palladium, which, in terms of so-called poor EXHAUST gas produced by the engine lean-burn, works effectively at lower temperatures than platinum. Despite the extremely high performance when using such a catalyst has to face the problem of insufficient supply of palladium, which is due to increase in recent years, price is on him and uncertainty of supply.

Another problem with using the existing three-component catalytic converters is that they are subject to aging at the termination of the fuel supply. The concept of "aging in the termination of fuel supply" reflects the performance deterioration of the catalytic Converter due to stop the flow of fuel when the internal combustion engine at full load. This situation often occurs when driving fast car when you need emergency deceleration. When high-speed driving, the engine operates at such ratios of air/fuel, which is slightly below the stoichiometric value. EXHAUST gas temperature can reach values that are much above 800°that is the reason for the temperature increase of the catalyst to higher values due to exothermic reactions of turning on the catalyst. In the event of a sharp slowdown modern electronic controls operation of the engine completely stop fuel flow to the engine, resulting in the value of the normalized ratio of the air/fuel (also called the coefficient of excess air λ) in the EXHAUST gas changes dramatically with the rich to the poor.

Such a large amplitude changes of the values of the normalized ratio of the air/fuel rich Abednego at high temperatures the catalytic Converter reduces the catalytic activity. Catalytic activity can at least partially restore prolonged engine operation with stoichiometric conditions ratio in the EXHAUST gas. The faster return catalytic activity after aging due to the termination of fuel supply, the higher the efficiency of the catalyst as a whole. Thus, accelerate the recovery of catalytic activity after aging due to the termination of fuel flow to the modern three-component catalytic converters is required.

The present invention is to provide such a three-component catalyst based on platinum and rhodium, which evince the same catalytic performance, and the famous palladium/rhodium catalysts, and which industry would be able to compete with the latter. Moreover, after high-temperature aging in poor EXHAUST so the catalyst must quickly fully restore its effectiveness in relation to the transformation of the three main present in the EXHAUST gas components. This catalyst should also have a high potential for conversion of nitrogen oxides to reduce shoobridge potential of treated EXHAUST gas.

These and other problems are solved by using a catalyst comprising internal and external the LOI on the inert substrate carrier, containing noble metals of the platinum group deposited on the core materials. This catalyst is characterized by the fact that the inner layer comprises platinum deposited on the first base and the first oxygen-storing component, and the outer layer comprises platinum and rhodium deposited on the second basis, and this outer layer further comprises a second accumulating oxygen component.

The catalyst according to the invention consists of a catalytic coating comprising inner and outer layers on an inert carrier, and, therefore, represents a so-called two-layer catalyst. The term "inner layer" means that he is the first layer catalytic coating deposited directly on the catalytic media. This inner cover layer "outer layer or the second layer. Subjected to processing such catalyst EXHAUST gas are in direct contact with the outer layer.

The concept of "material-based" or "basis" in the description of the present invention used as a powder material, which in finely dispersed form, i.e. in the form of small crystals with sizes in the range 1-10 nm, it is possible to precipitate the catalytically active components such as noble metals of the platinum group elements or other promoter components. For this reason, the specific area is poverhnosti (also known as the specific surface area, determined by nitrogen adsorption BET method in accordance with DIN 66132) of the core should not exceed 5 m2/, First and second accumulating oxygen components of the catalyst are also used in powdered form.

Not based on any theory, I believe that the contribution of the lower layer in the overall catalytic efficiency of the catalyst is mainly in the oxidation of hydrocarbons and carbon monoxide, whereas the main task of the external layer consists in the recovery of oxides of nitrogen. However, the outer layer also contributes, especially in the phase of cold start of the engine, the conversion of hydrocarbons and carbon monoxide.

Extremely high properties proposed in the invention catalyst in relation to aging at the termination of the fuel supply and conversion of nitrogen oxides is attributed mainly to the fact that in the outer layer of the second material basis precipitated only platinum and rhodium.

It was found that the deposition of platinum and rhodium on the same material basis reduces the cooldown of catalytic activity after exposure to conditions of poor EXHAUST gas at high temperatures. The result, in turn, is a higher efficiency of conversion of oxides of nitrogen during the entire cycle of movement of the vehicle. In to the text of the present invention the deposition of platinum and rhodium on the same material-based means, that platinum and rhodium dispersed on the same particles of the second material base, i.e. platinum and rhodium at least closely side by side on the same particles. Further improvements can be achieved by providing a tight contact between the two precious metals. How this can be achieved, further described below.

In accordance with this aspect of the invention causes aging three-component catalytic converters at the termination of the fuel supply can be that large amplitude changes of the values of the normalized ratio of the air/fuel from the rich to the poor at high temperatures of the catalyst reduces the catalytic activity, especially rhodium. In terms of stoichiometric or rich EXHAUST gas rhodium is recovered to almost zero oxidation state, which for the catalysis of the three components is the most effective condition. In poor EXHAUST gas and at high temperatures of the rhodium catalyst is oxidized to the level of oxidation of +3. In this state of oxidation of rhodium is less active for the conversion of three toxic components. Moreover, since the crystallographic structure Rh2O3is isomorphic to the relative Al2About3at temperatures exceeding 600°With, he is able to migrate the crystal lattice of the aluminum oxide or other isomorphic oxide basic composition M 2About3(where M denotes a metal atom), resulting in catalytic activity is constantly decreasing.

Thus, to return to its catalytic activity and prevent loss of rhodium in the crystal lattice of the aluminum oxide when the composition of the EXHAUST gas changes, returning to the stoichiometric rhodium need to recover as quickly as possible. In accordance with this aspect of the invention, the recovery of rhodium to the zero-state oxidation catalyzed by platinum. The more dense is the contact between the platinum and rhodium, the greater this effect recovery.

In addition, the trend Rh2O3migration in isomorphic oxide basis, you can limit the appropriate doping of these oxides. The favorable influence of the alloying components in the reducing conditions capable of forming the activated hydrogen. In the reducing conditions of the activated hydrogen promotes more rapid translation of rhodium oxide in the metal mold and, therefore, reduce to a minimum the further danger migration Rh2O3in the oxide basis. Suitable for this purpose alloying component is cerium oxide (cerium oxide). However, since the cerium oxide is also the ability to store and release oxygen, the amount of the oxide of the Church whom I used for doping should be small, as too high a content of cerium oxide in the oxide basis promotiom oxidation of rhodium.

Below the present invention is illustrated with reference to the attached drawing, which schematically shows the principle of measurement to determine the intersection points of the curves CO/NOx.

Below are examined in more detail the specific options of the catalyst, provided in accordance with the present invention.

The first and second bases of the catalyst may be the same or different. In a preferred embodiment, the first and second bases are selected from the group comprising silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, mixed oxides or mixtures thereof. The term "mixed oxide" refers to a homogeneous mixture of two or more oxides at the atomic level, which can be considered as a new chemical compound, whereas the term "mixture" refers to a mechanical mixture of two or more powdered oxide materials.

The most advisable to choose a basis of activated alumina, optionally supplemented with Zirconia or rich Zirconia mixed oxide containing zirconium dioxide. Activated alumina is characterized by specific area of poverhnosti 400 m 2/, They include different phases of the transition alumina, which are formed during the aging of hydroxides of aluminum at elevated temperatures in air (see Ullmann''s Encyclopedia of Industrial Chemistry, 5th ed., 1985, volume A1, str-562). For high-temperature resistant active aluminum oxide can be stabilized with 0.5-20 wt.% oxide of lanthanum. Such materials are commercially available. If aluminum oxide is used as the base material for platinum, commonly used stabilization of alumina oxide of barium (barium oxide) is less preferred because it is associated with the risk of formation of platinate barium.

The concept of "rich in Zirconia" means that the material contains at least more than 50 wt.%, preferably more than 60 wt.% and most preferably more than 80 wt.% zirconium dioxide, and the rest is accounted for yttrium oxide, neodymium oxide, calcium oxide (calcium oxide), silicon oxide, lanthanum oxide or cerium oxide, which provides stabilization of Zirconia under thermal loads. In the most preferred embodiment uses a mixed oxide type rich dioxide, zirconium dioxide, zirconium/cerium oxide. As the connection of pure Zirconia and stabilized Zirconia in the future, usually referred to collectively by the term "zirconocenes comp is element".

In addition to stable aluminum oxide and optional zirconocenes component of the inner or first layer of the catalyst includes accumulating oxygen material for improved conversion of three toxic components of the EXHAUST gas. It is well known that cerium oxide exhibits the ability to store oxygen. In poor EXHAUST cerium fully oxidized to the oxidation state of CE4+. In terms of rich EXHAUST gas, the cerium oxide emit oxygen and enters the oxidation state of CE3+. In the preferred embodiment, as is accumulating oxygen compounds instead of pure cerium oxide using such mixed oxide compounds as rich oxide, cerium oxide, cerium/zirconium dioxide with a concentration of cerium oxide 60-90 wt.% in terms of the total weight of the mixed oxide. Such materials are available with a specific surface area 20-200 m2/g and exhibit good thermal stability in relation to surface area. Further improvements can be achieved by stabilization of this material oxide, praseodymium, yttrium oxide, neodymium oxide, lanthanum oxide, or mixtures thereof. To stabilize enough to be the concentration of the stabilizing compounds in 0.5-10 wt.% in terms of the total weight of the stabilized material. Stabilization of accumulating kislorodoterapii based on cerium oxide using praseodymium oxide, the neodymium oxide, lanthanum oxide or their mixtures described in DE 19714707-A1.

In accordance with the present invention as the basis for platinum in the first layer are used as the core materials, and accumulate oxygen compounds. It was found that the deposition of platinum on only one of these materials leads to the deterioration of catalytic activity.

As accumulating oxygen material of the outer layer can be used a material which is identical to running the oxygen material of the inner layer or different from him. In the preferred embodiment use the same material for the inner and outer layers, primarily mixed oxides of cerium oxide/zirconium dioxide, stabilized oxide praseodymium. Second accumulating oxygen material of the outer layer should be maintained in the state in which he is free of rhodium. Deposition of rhodium on the second nakaplivaya oxygen material due to oxidation of rhodium would decontamination, consisting in reducing the reducing action of rhodium.

The outer or second layer may further include a number of active aluminum oxide in powdered form, which serves as a dilution of the material. This material may not necessarily be stabilized with lanthanum oxide or barium oxide.

Additionally improve the catalytic activity and thermal stability, adding a second layer of finely dispersed component selected from the group comprising yttrium oxide, neodymium oxide, lanthanum oxide or praseodymium oxide, and praseodymium oxide are preferred. These compounds can be introduced into the layer by adding a composition for coating the second layer soluble compounds, which is a precursor of these compounds.

The concept of "dispersed component" means that in contrast to the "powdery component of this material is added to the composition for coating in the form of soluble compounds predecessor, which acquires its final dispergirovannoyj form by calcining the catalytic coating. The average particle size of dispersed components may be in the range of 0.001-0.1 ám, while the average diameter of the particles of the powder components is usually in the range of 1-15 microns.

Dispersed component of the second layer performs many functions. First, it stabilizes the powder components (aluminiumoxide basis and the cerium oxide/zirconium dioxide as accumulating oxygen component) of the second layer from thermal degradation. Thus, in the case of adding, for example, oxide of praseodymium in dispersed form in the second layer of oxide of cerium/zirconium dioxide is not necessary to stabilize prewar the tion, because it is usually stabilized in situ in the process of obtaining coverage. Secondly, the oxide of praseodymium is also the ability to store and release oxygen, which improves the dynamic response of the finished catalyst, although the ability of praseodymium oxide to the accumulation of oxygen is not so clearly as cerium oxide.

The catalyst carrier used in the present invention, has the shape of a honeycomb monolithic element with many passing through it almost parallel channels. These channels is limited by the walls, which cause a catalytic coating comprising inner and outer layers.

Channels in the media define the path of flow of the EXHAUST gas of the internal combustion engine. When driving through these channels the EXHAUST gas to come into close contact with a catalytic coating, resulting in the toxic components contained in EXHAUST gas into harmless substances. The media can be made of any acceptable material, in particular of metal or ceramic materials, as is well known in the art. The channels are in the form of a homogeneous structure throughout the cross section of the media. The so-called density of cells (number of channels per unit cross-sectional area) can vary in the range of 10-200 cm-2Other acceptable carriers can include materials with the structure of poroplast with open pores. Can be used with metal or ceramic cellular plastics.

The inner layer catalytic coating is applied to the carrier with a flow rate of from about 50 to 250 g/l, and the outer layer is applied with a flow rate of 10-150 g/l volume of media. In the preferred embodiment, this inner layer includes 20-150 g/l of the first component framework and 10-100 g/l of the first accumulating oxygen component. The inner layer may further include 5-60 g/l of zirconium dioxide or zirconocene component. Platinum is contained in the first layer in concentrations of 0.01-5 wt.%, preferably 0.05 to 1 wt.% in terms of the total weight of the first layer. The concentration of platinum in terms of the volume of the catalyst carrier is 0.01-12.5 g/l, most preferably of 0.025 to 2 g/L.

In the most preferred embodiment, the first base comprises active alumina with a specific surface area in the range of 50-200 m2/g stabilized with lanthanum oxide, while the first accumulating oxygen component it is advisable to choose from the mixed oxides of the type-rich oxide, cerium oxide, cerium/zirconium dioxide, containing 60-90 wt.% cerium oxide and optionally stabilized with 0.5-10 wt.% oxide praseodymium (Pr6About11). I believe that such a composition of the first layer will strengthen its catalytic function for the oxidation of hydrocarbons (HC) and monoxi the and carbon (CO).

The outer layer catalytic coating comprises 5-100 g/l, preferably 5-20 g/l of the second substrate and 5-100 g/l, preferably 5-50 g/l of the second accumulating oxygen component. The outer layer may further include 5-60 g/l of activated alumina. In this outer layer on the second basis is applied platinum and rhodium. When compared with the inner layer, the preferred concentration of noble metals in recalculation on weight of the substrate material in the outer layer above. For example, the concentration of the combination of platinum plus rhodium can be selected in the range of 0.5-20 wt.% in terms of the mass of the second base material, and the preferred concentration in the range of 1-15 wt.%. These concentrations correspond to the concentrations in terms of the volume of the catalyst carrier in the range of 0.025-20 g/l, preferably in the range of 0.05 to 15 g/L.

As mentioned above, platinum, being in close contact with rhodium, in the outer layer contributes to the recovery of rhodium oxide, formed during periods of stopping fuel supply to the metallic state. To perform this task, the mass ratio between platinum and rhodium should be selected in the range from 5:1 to 1:3. The most preferred mass ratio ranging from 3:1 to 1:1.

As in the case of the inner layer, in a preferred embodiment, the second base is chosen from the active aluminium oxide the Oia with a specific surface area in the range of 50-200 m 2/g stabilized with lanthanum oxide, while the second accumulating oxygen component selected from mixed oxides of the type-rich oxide, cerium oxide, cerium/zirconium dioxide, containing 60-90 wt.% cerium oxide, optionally stabilized with 0.5-10 wt.% oxide praseodymium (Pr6About11). As noted above, the stabilizing oxide, praseodymium, or in another embodiment, the yttrium oxide, neodymium oxide or lanthanum oxide can also be achieved by adding these compounds to the second layer in the form of fine components.

In order to suppress the hydrogen sulphide in the first and second layers of the catalytic coating can optionally enter 1-40 g/l Nickel, iron or manganese component.

The catalyst according to the present invention can be manufactured in various ways, some of which are described below.

To obtain the inner layer on the channels of the carrier can be coated using aqueous composition for coating comprising a powder core materials of the inner layer (including the first accumulating oxygen material). Composition for coating in the context of the present invention is usually called a dispersion for coating. The coating technology on the media using such compositions for applying pokritikovali known to the person skilled in the art. Next, the coating is dried and calicivirus on the air. In a preferred embodiment, drying is carried out at elevated temperatures, up to 150°C. When the calcination of such coverage, the temperature should be 200-500°and a duration of 0.1-5 hours

After calcination platinum can be atomized in the supplied coating the carrier by immersing the monolithic material in a solution containing compound, the precursor of platinum. This solution can be an aqueous or non-aqueous (organic solvent) solution. You can use any connection-the platinum precursor, provided that the compound is soluble in the selected solvent and decompose during exposure to air at elevated temperatures. Examples of these platinum compounds are platinochloride acid, chloroplatinic ammonium hydrate platinum tetrachloride, dichlorocarbanilide platinum, dinitrogen platinum, platinum nitrate, tetramineral platinum and tetraaminopyrimidine platinum. After impregnation the floor again calicivirus in air at a temperature of 200-500°C.

Alternatively the inner layer can be obtained initially impregnated powdered materials of the inner layer in an aqueous solution of a soluble compound of the platinum precursor, drying, and calcining the impregnated Poroskov asnyk of material to the fuser on them platinum. Further, this catalyzed material used in the preparation of an aqueous composition for coating with the aim of obtaining coatings on the walls of the channels of the media. The coating is dried and calicivirus by the above method.

In a preferred method for the inner layer are preparing an aqueous dispersion of the powdery material of the inner layer. For the deposition and retention of platinum powder material dispersion in the dispersion is gently sprayed with a solution of compounds, the precursors of platinum and then the appropriate regulation of the pH of the dispersion to powdered materials precipitated the platinum compound to obtain the final composition for coating. In the processes of sputtering and deposition dispersion continuously stirred for quick and uniform distribution of the injected solution in the whole volume of the dispersion. The precipitated compound is firmly fixed on the core materials.

The method of deposition by sputtering is described in DE 19714732 a-1 and DE 19714707 a-1. In the description below, it is referred to as deposition through sputtering.

Suitable for the implementation of such a method of deposition of the compounds predecessors platinum are those already described above. In addition, can be used solubilization Amin platinum compounds, such as m tretinoinretin (IV) hexahydrate [(MEA) 2PtOH)6i.e. (OHC2H4-NH2CH3)2+PtIV(OH6)], ethanolamine (IV) hexahydrate [(EA)2Pt(OH)6ie (OH-C2H4-NH3)2+PtIV(OH6)] and other organic derivatives of Quaternary ammonium salts. It is known that these anionic complex platinum compounds form a finely dispersed precipitation of metallic platinum.

These solubilization the amine compound precursor to form a highly basic aqueous solutions. As the substrate using the aluminum oxide by adsorption solubilization the amine compound precursor is easily fixed to the surface of aluminum oxide. Adsorbed materials can be fixed by chemical means, for example by neutralization of the dispersion.

Thus prepared dispersion for coating further used for coating the walls of the channels of the media. The coating is dried and calicivirus in the air.

The above method of deposition by sputtering is preferred because it includes only one stage drying and calcination, whereas each of the first two methods require two stage drying and calcination.

In a preferred embodiment, the first accumulating oxygen component for the bottom layer the choice is up from mixed oxide type rich oxide, cerium oxide, cerium/zirconium dioxide, stable oxide of praseodymium. Can be used already stabilized material or stabilization can be carried out in separate stages. The cerium oxide/zirconium dioxide can also stabilize the oxide formed in situ in the process of getting the first layer. For this purpose can be prepared with a solution of compounds of the precursor of the oxide of praseodymium, in which is dispersed cerium oxide/zirconium dioxide. Next, this dispersion to precipitate compounds predecessor on the cerium oxide/Zirconia sprayed ammonia. Acceptable compounds predecessors praseodymium serve acetate and praseodymium nitrate.

Then the resulting dispersion is used to prepare the final composition for coating an additional addition of active aluminium oxide and optional powder zirconocene component. Then powdered materials of this dispersion catalyze platinum by the above deposition by sputtering.

After deposition on the carrier of the inner layer, the outer layer can be obtained as follows.

First impregnation second warp aqueous solution of soluble compounds, the precursors of platinum and rhodium, and drying and calcining this impregnated basics of preparing a basis, the carrying platinum and rhodium. After catalysis the very foundations dispersed in water second nakaplivalsya oxygen connection and additional activated alumina to obtain a composition for coating. This composition for coating is used to produce the outer cover over the inner layer. In conclusion, the media coverage again dried and calicivirus by the above method.

Acceptable compounds predecessors platinum are those already mentioned above. As compounds of rhodium precursor can effectively use examinermichael, trichloride rhodium, carbonylchloride rhodium, hydrate trichloride rhodium, rhodium nitrate and rhodium acetate, but the preferred rhodium nitrate.

Second base can be impregnated with compounds precursors of platinum and rhodium or sequentially in any order or simultaneously using a single common solution. However, as indicated above, it is necessary to achieve close contact between the platinum and rhodium. It was found that in this respect the most appropriate first deposition on the base material by the above deposition by sputtering first platinum, and then rhodium. To this end, the connection-the platinum precursor selected from solubilizing the amine compounds of platinum type ethanolamine (IV) hexahydrate, and the deposition of platinum implement appropriate regulation of the pH of the dispersion. After deposition of platinum basis, not dry and not calicivirus and directly ZAT is m solution of acidic compounds of rhodium precursor, such as rhodium nitrate, precipitated rhodium.

For this reason, the aqueous dispersion for coating, designed to produce the outer layer, obtained by cooking from the second base material, preferably of active aluminum oxide, the first aqueous dispersion and subsequent spraying an aqueous solution solubilizing the amine compounds of the platinum precursor in the dispersion. Active aluminum oxide is easily adsorbs solubilizing the amine compound, the precursor of platinum. After that, in such a dispersion is sprayed with an aqueous solution of acidic compounds of rhodium precursor and the pH value of the dispersion is appropriately regulate with the aim of securing the second base compounds of platinum and rhodium.

Further catalyzed the second substrate from the liquid phase of the first dispersion can be distinguished, as well as dry and calcinate with its subsequent re-dispersion together with the second oxygen-storing component and optional additional number of active aluminum oxide for the preparation of a dispersion for coating, designed to receive the outer layer. For calcination catalyzed base material is most appropriate to apply the spray or rapid calcination. In the case of spray or e is press-calcination wet material is sprayed into the stream of hot gas with a temperature in the range of 700-1000° With, resulting in several seconds or even within less than a second to happen drying and decomposition of compounds predecessors. This ensures the high dispersion of the formed crystallites with noble metals.

However, in the preferred embodiment, the intermediate stage of drying and calcination catalyzed base material exclude, and the second accumulating oxygen component and optional additional active aluminum oxide are added directly to the first dispersion containing the catalyzed second basis. This possibility exists because when the described deposition by sputtering platinum and rhodium firmly fixed on the second base material.

Next, the thus prepared dispersion for coating use when getting on top of the inner layer of the outer layer, followed by drying and calcining media coverage. This latter method of obtaining the outer layer preferably the previously described method, since it avoids a separate heat treatment catalyzed second base.

Preferred second accumulating oxygen component selected from the mixed oxide type oxide of cerium/zirconium dioxide, stabilized oxide praseodymium. Stabilization of cerium oxide/deoxidation can effectively be achieved by the implementation of in situ above-described method. With this purpose, the dispersion comprising alumina, platinum-catalyzed and rhodium, enter solution connection predecessor praseodymium, cerium oxide/zirconium dioxide and optional aluminum oxide. The resulting dispersion is then used for applying the second coating layer. By calcining this layer connection-praseodymium precursor on the surface of the powdery material of the second layer forms a fine praseodymium. Due to this, the cerium oxide/zirconium dioxide stabilized against thermal loads, and due to the ability of praseodymium accumulate oxygen, it also improves the ability to accumulate oxygen catalyst.

In General, in the most preferred embodiment of the invention the inner layer catalyst comprises platinum deposited on the active aluminum oxide and mixed oxide type rich in cerium oxide cerium oxide/zirconium dioxide, and the outer layer of the catalyst comprises platinum and rhodium deposited on the active alumina, and, in addition, the outer layer comprises a mixed oxide of the type-rich oxide, cerium oxide, cerium/zirconium dioxide. This catalyst may be prepared in the following way:

a) preparation of a solution of the compound of praseodymium precursor, the addition of the mixed oxide in the form of cerium oxide/dio the sid of zirconium and regulation of the pH of the dispersion thus, to cause the precipitation of the compounds predecessor praseodymium oxide cerium/zirconium dioxide,

b) then adding to the dispersion from step (a) aluminiumoxide and optional zirconocene component

C) spraying the dispersion from stage (b) solution of the compound of the platinum precursor and its deposition on alumina, cerium oxide/zirconium dioxide and optional zirconocenes component with a first composition for coating, which is designed for receiving the inner catalyst layer,

g) applying on a monolithic carrier coating using the first composition for coating, and drying and calcining the coating with obtaining thus the carrier coated with the inner layer,

d) preparation of dispersion of active alumina and dispersed in the dispersion solution of platinum compounds,

(e) subsequent dispersion in dispersion from stage d) aqueous solution of soluble compounds of rhodium precursor and the regulation of the pH of the dispersion with obtaining thus the dispersion of active aluminum oxide, catalyzed with platinum and rhodium,

g) adding to the dispersion from step (e) active aluminum oxide, mixed oxide in the form of rich cerium oxide cerium oxide/zirconium dioxide and optionally nastorazhivanie predecessor praseodymium with obtaining a second composition for coatings, designed for the outer layer catalyst

C) the application of the second composition for coating during application of the outer layer over the inner layer and

I) drying and calcining the monolith media coverage.

In the most preferred embodiment, the active alumina used in stages a) and (g) for the inner and outer layers, stabilize 0.5 to 20 wt.% oxide of lanthanum. In the above method, the material basis and the cerium oxide/zirconium dioxide stabilized with praseodymium oxide in situ. Alternatively stabilization of cerium oxide/Zirconia oxide, praseodymium, yttrium oxide, neodymium oxide, lanthanum oxide or mixtures thereof can be carried out in separate stages with the use of these alloying compounds impregnation, deposition by sputtering, by coprecipitation or joint thermal hydrolysis.

To stabilize the cerium oxide/zirconium dioxide-impregnated powdered cerium oxide/zirconium dioxide moistened with an aqueous solution of compounds, the precursors of the target alloying element, and then dried and calicivirus. With this purpose they have resorted to the method of saturation of the pore volume. In this case, compound precursor is dissolved in such a quantity of water, which corresponds to the absorptivity of the cerium oxide/zirconium dioxide.

Deposition with ASD what Elenium already described above for the case of deposition of compounds of noble metals on the core materials.

To stabilize the cerium oxide/zirconium oxide by coprecipitation prepare the General solution of the compounds, the precursors of cerium oxide and zirconium dioxide, as well as connections predecessor stabilizing element. Then these three compounds simultaneously precipitated by adding acceptable precipitator. For example, the cerium oxide/zirconium dioxide stabilized with praseodymium, can be obtained by preparing the General solution of cerium nitrate, zirconium nitrate and praseodymium nitrate and the addition of ammonium carbonate or ammonium oxalate, resulting cerium, zirconium and praseodymium simultaneously deposited as carbonates or oxalates. After filtration and drying target stabilized cerium oxide/zirconium oxide produced by calcination. Alternatively, the coprecipitation can also be the primary environment.

To stabilize the cerium oxide/zirconium dioxide joint thermal hydrolysis of hydroxycitrate cerium, hydroxycitrate zirconium and hydroxycitrate alloying element to prepare a colloidal solution. Then this colloidal solution temperature dehydrate. As a result, hydroxycitrate decompose to form the corresponding oxides. Joint thermal hydrolysis is described, for example, in WO 98/16472.

Improved properties proposed in the invention catalyst is proillyustrirovany in the following examples.

The drawing schematically illustrates the principle of measurement when determining the points of intersection of the curves of CO/NOx.

Comparative example 1

Conventional single-layer platinum-rhodium catalyst W1 (comparative catalyst 1) was prepared as follows.

Carbonate of cerium and zirconium in the night was treated with water and acetic acid at room temperature with partial receipt of the corresponding acetates. In the resulting dispersion was added to a stabilized aluminum oxide and bulk cerium oxide with a small specific surface area. After wet grinding this slurry by conventional technology immersion coated monolithic carrier. The substrate with the coating was dried in air and was caliciviral in air for 2 h at 500°C.

After washing, covering the total amount of material absorbed by the media, was 205 g/l, which corresponded to 112 g/l stabilized aluminum oxide, 34 g/l of bulk cerium oxide, 34 g/l of cerium oxide and 25 g/l of zirconium dioxide, both of the latter compound was obtained from acetate precursors.

Washed the coating layer was impregnated platinum and rhodium salts, not containing chlorides (tetramineral platinum and rhodium nitrate). When the concentration of 1.41 g/l (40 g/ft3) the mass ratio between platinum and rhodium was 5Pt/1Rh.

Sostavitvsego catalyst are shown in table 1.

Table 1:

The composition of comparative catalyst W1
ComponentConcentration [g/l]
Aluminum oxide (stabilized 3 wt.% La2O3)

CeO2(bulk)

CeO2(former acetate)

ZtO2(former acetate)
112

34

34

25
The total content of oxides205
Platinum

Rhodium
1,175

0,235
The total noble metal content1,41

Example 1

Two-layer catalyst K1 in accordance with the invention was prepared as follows.

The first (inner) layer

In the solution of praseodymium acetate was administered rich in cerium accumulating oxygen component (70 wt.% cerium oxide, 30 wt.% zirconium dioxide). Adjustable spray ammonia and stirring for about 30 min praseodymium acetate besieged on the cerium oxide/zirconium dioxide. After this was added to a stabilized aluminum oxide (3 wt.% La2O3, 97 wt.% Al2O3and bulk Zirconia. Next, the slurry was sprayed a solution of platinum compounds [(EA)2Pt(OH)6] and the corresponding regulation of the pH of the dispersion by adding at ssnoi acid on aluminum oxide and cerium oxide/Zirconia besieged platinum. After grinding of the slurry in the slurry was dipped a monolithic carrier for the first layer.

Final after washing cover the amount of absorbed material was 160 g/l At the end of the first layer was dried, followed by calcining in air at 500°C.

Obtaining a second (external) layer

Water was dispersively stabilized aluminum oxide (4 wt.% La2O3, 96 wt.% Al2O3). After that sprayed not containing platinum chloride salt [(EA)2Pt(OH)6], which was easily adsorbiroval aluminum oxide. Then sprayed rhodium nitrate. Both catalytic component was fixed on aluminiumoxide the basis of the regulation of pH values.

In conclusion, in the washed floor was injected aluminum oxide, praseodymium acetate and rich in cerium oxide accumulating oxygen component (70 wt.% cerium oxide, 30 wt.% zirconium dioxide).

Before applying on a monolithic substrate covering the pH value of the slurry is brought up to approximately 6, and crushed. After washing, covering the total amount of material absorbed by the second layer was 70 g/l, the Catalyst was dried and was caliciviral in air at 500°C.

The composition of the finished catalyst are shown in tables 2 and 3.

Table 2:

The composition of DNAs is Rennie catalyst layer K1
ComponentConcentration [g/l]
Aluminum oxide (stabilized 3 wt.% La2O3)

CeO2/ZrO2(70 wt.% CeO2; 30 wt.% ZrO2)

Pr6O11< / br>
ZrO2
80

51,7

4,3

24
The total content of oxides160
Platinum0,94

Table 3:

The composition of the outer layer of the catalyst K1
ComponentConcentration [g/l]
Aluminum oxide (stabilized 3 wt.% La2O3)

CeO2/ZrO2(70 wt.% CeO2; 30 wt.% ZrO2)

PrO11< / br>
Aluminum oxide (unstabilized)
10

18,5

1,5

40
The total content of oxides70
Platinum

Rhodium
0,235

0,235
The total noble metal content0,47

The mass ratio between platinum and rhodium in the upper layer was 1Pt/1Rh. The total content of platinum and rhodium was equal to 1.41 g/l (1,175 g Pt/l and 0,235 g Rh/l) at a mass ratio 5Pt/1Rh (cumulative mass ratio for both layers).

Comparative example 2

Bimetallic catalysis is Thor W2 was prepared by the same method, as the catalyst of example 1. Unlike example 1, platinum in the first layer besieged on a separate stage cooking only aluminum oxide before preparing slurry for coating, intended for the treatment of this first layer.

Comparative example 3

Two-layer catalyst TC3 was prepared by the same method as that of the catalyst of example 1. Unlike example 1, the entire quantity of platinum was applied only on the first layer. Thus, to obtain comparative catalyst of platinum and rhodium were completely separated from each other.

Evaluation of catalysts

a) the Test engine

The catalysts in accordance with the above-described examples and comparative examples were first subjected to aging with a working internal combustion engine (an engine capacity of 2.8 liters) for 76 hours at a temperature of EXHAUST gas before entering the catalyst 850°C. After this was determined operating temperature of the catalyst for the conversion of HC, CO and NOxand the point of intersection of the CO/NOx. The concept of working temperature mean temperature Of the Year, when using the catalyst of the transformation are 50% of the toxic components of the EXHAUST gas. For HC, CO and NOxthe working temperature may be different.

Conducted two separate experiment with aging. In the first experiment, the sample to which telesfora K1 and comparative catalyst W1 subjected joint aging, whereas in the second experiment, a joint aging subjected to another sample of catalyst K1 and comparative catalysts W2 and TC3. Since experiments with aging in exactly reproduce was impossible, the catalysts after two experiments with aging were somewhat different. Thus, to compare was only the catalyst, which were subjected to aging in the course of conducting the same experiment.

Determining the operating temperature was carried out at flow rate of 65,000 h-1with a gradual increase EXHAUST gas temperature (38° K/min) of the engine.

The principle of determining the intersection points of the curves CO/NOxschematically represented in the drawing. The air excess factor λ an air-fuel mixture supplied to the engine is periodically changed from 0.98 (enriched air-fuel mixture) to 1.02 (lean air-fuel mixture) and Vice versa. For each of the values λ=0.98 and λ=1,02 length of stay was set equal to 1 min. switching from mode choke in the mode lean back and also forth for 3 minutes Corresponding to the fluctuation of values To that shown on the drawing (lower graph). The drawing shows the corresponding graphs transformations WITH and NOx. When working on a lean mixture, the transformation is essentially equal to 100%, and when working on choke it drops to about 50-60%. The conversion of NOxis reversed, as can be seen form the corresponding curve of the conversion of NOx. When working to choke the degree of conversion of NOxapproaches 100%, whereas when working on a lean mixture, the degree of conversion of NOxdrops to values in the range of 50-60%. When set to λ=1 both graph transformation intersect. The corresponding degree of transformation represents the maximum conversion that can be achieved for both CO and NOx. The higher this intersection point, the better the dynamic characteristics of catalytic activity of the catalyst, respectively, of the catalytic Converter.

When described directly above the point of intersection using the so-called static jitter values λ. You can also use dynamic jitter values λ. In this case, the graph of the fluctuations in the values λ additionally modulate with a frequency of 1 or 0.5 Hz. The amplitude may be equal to ±1 a/T or ±0,5 a/T (air/fuel). This amplitude is usually greater than the amplitude of the graph of the fluctuations ±0,02 λ, which corresponds to the amplitude of the a/T±0,3.

Dynamic point of intersection for the catalysts of the previous examples opredeleniya flow rate of 65,000 h -1and when the EXHAUST gas temperature of 450 and 400°C. When the EXHAUST gas temperature to 450°With the ratio in the fuel-air mixture is modulated with a frequency of 1 Hz and amplitude 1/T (1 Hz ± 1 air/fuel). When the EXHAUST gas temperature of 400°With the amplitude modulation was reduced to 0.5 a/T (1 Hz ± 0.5 air/fuel).

The results of the determinations are presented in tables 4 and 5. Table 4 compares the data for catalysts, which were subjected to aging during the first experiment with aging, whereas in table 5 compares the data for catalysts, which were subjected to aging during the second experiment with aging.

Table 4
CatalystT50[°]CO/NOx[%]
HCCONOx1 Hz ± 1/T1 Hz ± 0.5 V/T
K13603633548488
W13874073827662

Notes: SK denotes the comparative catalyst refers To a catalyst that T50indicates the operating temperature for 50%conversion.

Table 5
CatalystT50[°]CO/Nox[%]
HCCONOx1 Hz ± 1/T1 Hz ± 0.5 V/T
K13663553549087
W237337435985
TC33893913797279

b) Testing the model gas

After aging of the catalysts of example 1 and comparative example 3 for 16 h at 985°in the depleted mixture of synthetic gas containing 6 vol.% O2, 10% vol. H2O, 20 ppm million SO2and the rest of N2point of intersection of the curves of CO/NOxwas determined at the temperature of the gas mixture 400°and flow rate 100000 h-1. The intersection point was determined at three different concentrations of SO2(0.5 and 20 ppm million) in this gas mixture. The results are presented in table 6.

Table 6
CatalystCO/Nox[%]
0 part./million SO2 5 frequent./million SO220 frequent./million SO2
K1656152
TC3423530

Example 2

In accordance with example 1 is additionally produced a number of 4 different catalysts K2, K3, K4 and K5. Unlike example 1, all the catalysts were made with a total content of noble metals 2,12 g/l (60 g/m3). The mass ratio between platinum and rhodium in the upper layer was varied to determine its effect on the catalytic properties of the catalysts. Distribution of precious metals in these supported catalysts are presented in table 7.

Table 7:

Distribution of noble metal
CatalystThe inner layerThe outer layerThe outer layer of Pt/RhThe inner layer Pt/Rh
Pt [g/l]Pt [g/l]Rh [g/l]
K21,410,350,351:15:1
K31,730,0350,351:105:1
Q40,71 1,060,353:15:1
C51,770,00,350:15:1

To determine the intersection points of the curves CO/NOxall four of the catalyst was subjected to aging for 12 h at a temperature of EXHAUST gas before entering the catalyst 1100°using a mixture of synthetic gas containing 6 vol.% O2, 10% vol. water vapor, 20 ppm million of sulfur dioxide and the rest is nitrogen.

Static point of intersection for these catalysts was determined when the EXHAUST gas temperature of 400°and flow rate 100000 h-1. During this test, the coefficient 1 of the exhaust gas increased from 0.98 to 1.02 for 5 min. Value And 1,02 kept constant for 1 min Then within 5 min to a value of 1 was again reduced to 0.98. After 1 min of inactivity this cycle is again repeated 2 times. In table 8 parameters of the intersection points of the curves of CO/NOxare average values for the last two cycles of tests.

Table 8:

The point of intersection of the curves of CO/NOx
CatalystCO/Nox[%] static point crossing
K290
K3 55
Q494
C5<30*)

Note: *indicates that no point of intersection.

For these definitions, used a model gas of the following composition:

To cause oscillation of the values λ the oxygen content in the model gas was varied in the range of 0.93-1,77%vol.

Example 3

In accordance with example 1 produced two additional catalyst K6 and K7 with a total noble metal content of 1.41 g/l (40 g/ft3). In the manufacture of the catalyst K6 worked exactly as in example 1, while in the manufacture of the catalyst C7 sequence impregnation of platinum and rhodium in the second basis was changed on the back: the beginning on activated aluminiumoxide basis besieged rhodium and only then platinum.

For both catalysts were tested in order to determine the behavior of their intersection points of the curves CO/NOxand to determine their operating temperatures. The results obtained are summarized in table 9.

Table 9
CatalystT50[°C]CO/NOx[%]
HCCONOx 1 Hz ± 0,25 a/T1 Hz ± 0.5 V/T1 Hz ± 1/T
K6360362354999590
K7359355353979082

From the results shown in table 9, one can see that the dynamic behavior of the catalyst K6 much better than catalyst C7. Not based on any theory, it is believed that this effect can be explained tighter contact between the platinum and rhodium, when first precipitated platinum, and then rhodium.

Example 4

Analogously to example 1 produced four additional catalyst K8, K9, K10 and K, but by making the following changes. The General asked the noble metal content was equal to 1.77 g/l (50 g/ft3).

The ratio of platinum/rhodium changed so that it was 3:2. In addition, the dispersion for coatings for the inner layers of catalysts K9-C in powder form was added various amounts of MnO2and NiO. These suppress the hydrogen sulphide components were introduced into the dispersion for coating after spraying compounds of platinum.

To determine the allocation of these catalysts for hydrogen sulfide their first saturated sulfur under the conditions of Bednogo (at flow rate of 65,000 h -1temperature 550°With value λ 1,01, approximate sulfur content in fuel 200 ppm million and the approximate period of saturation >0.5 h). After this is λ reduced to 0.88 and installed on the test line of the mass spectrometer was determined by hydrogen sulphide. Peak the maximum number of allocated hydrogen sulfide catalysts for K8-C specified in table 10.

Table 10:

The suppression of the allocation of H2S using MnO2and NiO.
CatalystBoth layers of Pt/RhThe total number of Pt+Rh [g/l]The content in the inner layer of the vast selection of H2S component [g/l]The maximum number of H2S [part./million]
K83:11,77750
K93:21,7720 MnO2380
K103:21,7740 MnO2330
C3:21,775 NiO100

Example 5

The catalysts in accordance with the invention do not contain palladium. However, they allocate a relatively small quantity is of hydrocarbons, carbon monoxide and nitrogen oxides as catalysts, which are used palladium and rhodium.

Another object of the invention is to reduce the cost of platinum group metals (PGM) in the new platinum-rhodium catalysts in comparison with the cost of PGM in the known two-layer palliatieve catalysts, shown in April 1999 Thus, in accordance with example 1 was prepared catalysts with different total content of noble metals and varying the ratio of platinum/rhodium, and they were compared on indicators such as activity by EXHAUST aftertreatment and cost PGM.

The catalysts were tested in a vehicle that is certified in accordance with EU norm-II, as the main catalytic converters installed under the floor of the body, with the ratio of the volume of catalyst/engine capacity of 0.67. After aging for 16 hours at 985°With the parameters of the catalysts was determined at 10% vol. water in nitrogen. In accordance with the test cycle, as defined in the new European norm MVEG-EU III, the test is performed on a cold start in stoichiometric conditions.

Table 11 presents the relative emission levels with values for palliatieve comparative catalyst (14Pd/1Rh), normalized to 100.

Table 11:

The relative emission levels in terms of the cost of PGM
The total PGM content [g/l]The ratio of PGMThe relative emission levelsThe cost PGM
HCCONOx
3,5314Pd/lRh100100100100
1,415Pt/lRh11911011251
1,773Pt/2Rh92918375
3,3245Pt/2Rh128108110108
3,899Pt/2Rh807556142

How should the data of table 11, on the conversion of HC, CO and NOxstrongly influenced by the content of rhodium, and for a given target level of emissions reduction in the content of platinum in favor of the content of rhodium is favorable. While, for example, when the total content is 1.77 g/l enriched with rhodium component (3Pt/2Rh) for vehicles certified according to the standard EU-II, is characterized by lower level of emissions of all the three toxic components in comparison with Pd/Rh pattern (of 3.53 g/l, 14Pd/1Rh), the options for high platinum content of 3.32 g/l (45Pt/2Rh) below results of the composition with the content of 1.77 g/l (3Pt/2Rh), despite a higher total content and definitely more than the high cost of noble metals.

For specialists in this field of technology is the obvious possibility of other variants and modifications, which should be considered as included by the scope of the attached claims.

1. Catalytic Converter, comprising inner and outer layers on an inert carrier containing noble metals of the platinum group deposited on a material basis, and accumulate oxygen components, wherein the inner layer comprises platinum deposited on the first base and the first nakaplivaya oxygen component, and the outer layer comprises platinum and rhodium deposited on the second basis, and this outer layer further comprises a second accumulating oxygen component.

2. A catalytic Converter according to claim 1, characterized in that the first and second bases are the same or different and represent a compound selected from the group comprising silicon dioxide, aluminum oxide, titanium dioxide, zirconium dioxide, mixed oxides and their mixtures with mixed oxide in the form of enriched dioxide zirconium dioxide zirconium/cerium oxide.

3. Catalyti the mini Converter according to claim 2, characterized in that the first and second bases are activated alumina, stabilized with 0.5-20 wt.% oxide of lanthanum.

4. A catalytic Converter according to claim 3, wherein the first base further includes zirconocenes component.

5. A catalytic Converter according to claim 1, characterized in that the first and second accumulating oxygen components are the same or different and represent a mixed oxide compound in the form of rich cerium oxide cerium oxide/zirconium dioxide.

6. A catalytic Converter according to claim 5, characterized in that ceriated/zirconocene mixed oxide compounds stabilize an oxide of praseodymium, yttrium oxide, neodymium oxide, lanthanum oxide, or mixtures thereof.

7. A catalytic Converter according to claim 6, wherein the outer layer further comprises activated alumina.

8. A catalytic Converter according to claim 1, wherein the outer layer further comprises fine yttrium oxide, neodymium oxide, lanthanum oxide or praseodymium oxide.

9. A catalytic Converter according to claim 1, characterized in that platinum and rhodium are contained in the second basis in tight contact with each other.

10. A catalytic Converter according to one of claims 1 to 9, characterized in that the carrier has a honeycomb structure is about many passing through it almost parallel channels, moreover, these channels is limited by the walls, which caused the internal layer material consumption from about 50 to 250 g/l and applied outer layer material consumption 10-150 g/l volume of the media.

11. The catalytic Converter of claim 10, wherein the first base is contained in the amount of 20-150 g/l, the first accumulating oxygen component contained in an amount of 10-100 g/l, and zirconocene basis is contained in the amount of 5-60 g/l

12. A catalytic Converter according to claim 11, characterized in that the platinum in the inner layer is contained in a concentration of 0.01-5 wt.% in terms of the total weight of the inner layer.

13. A catalytic Converter according to item 12, wherein the second base is contained in an amount of 5-100 g/l, the second accumulating oxygen component contained in an amount of 5-100 g/l, and activated alumina is contained in an amount of 5-60 g/l

14. A catalytic Converter according to item 13, wherein the platinum and rhodium in the outer layer are contained in a concentration of 0.5-20 wt.% in terms of the total weight of the outer layer, and the mass ratio of platinum/rhodium is from 5:1 to 1:3.

15. The catalytic Converter on 14, characterized in that at least one of the inner and outer layers further includes from about 1 to 40 g/l Nickel, iron or manganese component

16. A catalytic Converter according to claim 1, wherein the inner layer comprises platinum deposited on the active aluminum oxide and mixed oxide fuel in the form of rich cerium oxide cerium oxide/zirconium dioxide, and the outer layer comprises platinum and rhodium deposited on the active aluminum oxide, and the outer layer further comprises a mixed oxide in the form of rich cerium oxide cerium oxide/zirconium dioxide, and this catalyst can be prepared by

a) preparation of a solution of the compound of praseodymium precursor, adding mixed oxide in the form of cerium oxide/zirconium dioxide and regulating the pH of the dispersion in such a manner as to cause the precipitation of the compounds of the predecessor praseodymium oxide cerium/zirconium dioxide,

b) adding to the dispersion from step (a) active aluminum oxide,

C) spraying the dispersion from stage (b) solution of the compound of the platinum precursor and the deposition of aluminum oxide and cerium oxide/zirconium dioxide with the first composition for coating designed for the inner layer catalyst

g) coating on a monolithic carrier coating using the first composition for coating, and drying and calcination of the coating with obtaining thus the carrier of the inner layer cover,

d) preparation of dispersion of active aluminum oxide and dispersion in the dispersion solution of platinum compounds,

(e) subsequent dispersion in dispersion from stage d) solution of soluble compounds of rhodium precursor and regulation of the pH of the dispersion to obtain thus water dispersion of active aluminum oxide, catalyzed with platinum and rhodium,

g) adding to the dispersion from step (e) active aluminum oxide, mixed oxide in the form of rich cerium oxide cerium oxide/zirconium dioxide

C) use this second composition for coating during application of the outer layer over the inner layer and

I) drying and calcination of the monolithic media coverage.

17. A catalytic Converter according to item 16, characterized in that the active aluminum oxide with stages b) and d) stable 0.5 to 20 wt.% oxide of lanthanum.

18. A catalytic Converter according to item 16, characterized in that stage b) add additional zirconocenes component.

19. A catalytic Converter according to item 16, characterized in that the dispersion from step d) was added a solution of compounds of praseodymium precursor.

20. A method of manufacturing a catalytic Converter according to claim 1, characterized in that

a) on the walls of the channels of the carrier are coated with whom oppozitsii for coatings, containing powdered materials, comprising the first base material and the first accumulating oxygen component

b) the coating is dried and calicivirus,

C) a carrier coated is immersed in a solution of a soluble compound of the platinum precursor and the coating calicivirus and

d) on top of the inner layer is applied outer layer.

21. A method of manufacturing a catalytic Converter according to claim 1, characterized in that

a) a powder material including a first base material and the first accumulating oxygen component, is subjected to catalysis by impregnation with a solution of a soluble compound of the platinum precursor and the materials are dried and calicivirus for the fuser to them platinum,

b) prepare the aqueous composition for coatings catalyzed materials from stage a) and on the walls of the channels of the first carrier coated with this composition for coatings

C) the coating is dried and calicivirus and

d) on top of the inner layer is applied outer layer.

22. A method of manufacturing a catalytic Converter according to claim 1, characterized in that

a) prepare a dispersion of the powdered materials, comprising the first base material and the first accumulating oxygen component, and sprayed solution dissolve the CSOs connection predecessor platinum,

b) compounds of platinum fix on all powdered materials by regulating the pH of the dispersion to obtain compositions for coatings,

C) on the walls of the channels of the carrier are coated from aqueous compositions for coating with stage a),

d) the coating is dried and calicivirus and

d) on top of the inner layer is applied outer layer.

23. The method according to any of PP-22, characterized in that

a) a second base impregnated with a solution of soluble compounds of platinum precursor compounds of rhodium and soaked the dried basis and calicivirus obtaining catalyzed framework

b) prepare the aqueous composition for coating using catalyzed fundamentals, second accumulating oxygen component and an additional amount of activated alumina and

C) the composition for coatings used for applying the outer layer over the inner layer.

24. The method according to any of PP-22, characterized in that

a) prepare a dispersion of the second base material and sprayed with a solution of a soluble compound of the platinum precursor,

b) in the dispersion from step (a) is sprayed with a solution of soluble compounds of rhodium precursor and regulate the pH of this dispersion with obtaining thus the basics, catalyzed the Oh platinum and rhodium,

in) of the dispersion from stage (b) prepare a composition for coating by adding a second accumulating oxygen compounds and additional number of active aluminum oxide,

g) the composition for coatings used for applying the outer layer over the inner layer and

d) a monolithic carrier coated and dried calicivirus.



 

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EFFECT: enabled preparation of catalyst with relatively high activity and selectivity, low carbon sedimentation velocity, and prolonged lifetime in naphtha reforming processes.

11 cl, 6 dwg, 4 tbl

FIELD: methods of production a synthesis gas.

SUBSTANCE: the invention is pertaining to the process of production of hydrogen and carbon oxide, which mixture is used to be called a synthesis gas, by a selective catalytic oxidation of the hydrocarbonaceous (organic) raw material in presence of the oxygen-containing gases. The method of production of the synthesis gas includes a contacting with a catalyst at a gas hourly volumetric speed equal to 10000-10000000 h-1, a mixture containing organic raw material and oxygen or an oxygen-containing gas in amounts ensuring the ratio of oxygen and carbon of no less than 0.3. At that the process is conducted at a linear speed of the gas mixture of no less than 2.2 · 10-11 · (T1 + 273)4 / (500-T2) nanometer / s, where: T1 - a maximum temperature of the catalyst, T2 - a temperature of the gas mixture fed to the contacting. The linear speed of the gas mixture is, preferably, in the interval of 0.2-7 m\s. The temperature of the gas mixture fed to the contacting is within the interval of 100-450°C. The maximum temperature of the catalyst is within the interval of 650-1500°C. The technical effect is a safe realization of the process.

EFFECT: the invention ensures a safe realization of the process.

10 cl, 5 ex

FIELD: alternate fuel manufacture catalysts.

SUBSTANCE: invention relates to generation of synthesis gas employed in large-scale chemical processes such as synthesis of ammonia, methanol, higher alcohols and aldehydes, in Fischer-Tropsch process, and the like, as reducing gas in ferrous and nonferrous metallurgy, metalworking, and on gas emission detoxification plants. Synthesis gas is obtained via catalytic conversion of mixture containing hydrocarbon or hydrocarbon mixture and oxygen-containing component. Catalyst is a complex composite containing mixed oxide, simple oxide, transition and/or precious element. Catalyst comprises metal-based carrier representing either layered ceramics-metal material containing nonporous or low-porosity oxide coating, ratio of thickness of metallic base to that of above-mentioned oxide coating ranging from 10:1 to 1:5, or ceramics-metal material containing nonporous or low-porosity oxide coating and high-porosity oxide layer, ratio of thickness of metallic base to that of nonporous or low-porosity oxide coating ranging from 10:1 to 1:5 and ratio of metallic base thickness to that of high-porosity oxide layer from 1:10 to 1:5. Catalyst is prepared by applying active components onto carrier followed by drying and calcination.

EFFECT: increased heat resistance and efficiency of catalyst at short contact thereof with reaction mixture.

13 cl, 2 tbl, 17 ex

FIELD: inorganic synthesis catalysts.

SUBSTANCE: invention provides ammonia synthesis catalyst containing ruthenium as active ingredient supported by boron nitride and/or silicon nitride. Catalyst can be promoted by one ore more metals selected from alkali, alkali-earth metal, or rare-earth metals. Ammonia synthesis process in presence of claimed catalyst is also described.

EFFECT: increased temperature resistance of catalyst under industrial ammonia synthesis conditions.

4 cl, 6 ex

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