The method of applying a catalyst on a ceramic carrier

 

(57) Abstract:

The invention relates to catalytic chemistry and can be used when applying particles and films of catalytically active metals on the surface of the ceramic monoblock media. The proposed method comprises applying to the surface of the carrier composition containing dispersed platinum group metal in the organic component, followed by heating and firing. As the applied composition using ultrafine metal deposited on the naphthalene used as the organic component, the ultrafine metal has additionally also use silver, gold or alloys of the above metals. The technical result is a simplification of the method and increase the service life of the catalyst. 1 C.p. f-crystals, 2 tab.

The invention relates to catalytic chemistry, in particular for the application of the particles and films of catalytically active metals on the surface of the ceramic monoblock media.

Known method of applying a palladium on appropriate media (U.S. patent N 4833114, B 01 J 23/44, date of publ.27.07.88) by application to the surface of the solution dinitrophenolate with Pawlicki carrier with a solution of compounds of platinum group metals (U.S. patent N 5141912, B 01 J 23/26, date of publ. 29.06.89) with subsequent activation.

There is also known a method of producing the catalyst by deposition on a substrate of a noble metal such as platinum or palladium (application N 3926551, Germany, B 01 J 23/44, publ. 14.02.91).

However, these two methods in the case of impregnation compounds of metals suggest the presence of a porous medium and is not applicable for bulk carriers, and in the case of deposition (vacuum or plasma) suggest the presence of complex equipment.

Closest to the proposed invention is a method of applying a catalyst of platinum group metal (application Japan # 63 - 6267, B 01 J 23/40, date of publ.09.02.88) by applying to the medium a mixed solution in an organic solvent containing a platinum group metal in the form of fine powder and ions, with the addition of inorganic binder, followed by heating and firing.

The disadvantages of this method include the presence of inorganic binder to promote adhesion of particles or metal film to the substrate, which reduces the active surface of the metal. The presence of ionic compounds metal, decomposing at a temperature firing, Privodino undesirable impurities. The disadvantage of this method is the high firing temperature required for the decomposition of ionic compounds and promote adhesion of the metal to the substrate (700 - 800oC).

The task of the invention is to increase the service life of the catalyst by increasing the adhesion of the metal to the substrate and the exclusion of impurities contaminating the catalyst, and the simplification of manufacturing technology by reducing the temperature of the deposition process of the catalyst.

The problem is solved by a method of applying a catalyst on the ceramic carrier, comprising coating the surface of the carrier composition containing dispersed platinum group metal in the organic component, followed by heating and firing, when this composition is applied to the preheated carrier, as applied composition using ultrafine metal deposited on the naphthalene used as the organic component, and as the ultrafine metal has additionally also use silver, gold or alloys of those metals.

Before application of the composition of the ceramic carrier is heated to 90 - 100oC, heated Nan is>The task can be solved also by a method of applying a catalyst on the ceramic carrier, comprising coating the surface of the carrier composition containing dispersed platinum group metal in the organic component, followed by heating and firing the coating composition used ultrafine metal, dispersed in an organic component comprising terpineol with the addition of dimethylformamide in a ratio of 250 : 1 by weight.h., and as the ultrafine metal has additionally also use silver, gold or alloys of the above metals, each of which is injected into the organic component in the ratio of 1 : 50 by weight.h. The heat applied to the carrier of the composition is carried out at 100 - 120oC and subsequent annealing at 350 - 400oC.

Ultrafine particles of metals (smaller than 1 μm) have a high surface activity (including catalytic). However, they are difficult to maintain in the form of particles separated because they have a tendency to rapid building-block approach that entails the loss of valuable properties of their surface. Consequently, it is proposed to use particles of these metals deposited on the crystals of naphthalene as organic the walkie-talkie.

Due to ultradispersed particles of coating metal and mikroheranhvatho the surface of the carrier conduct low-temperature deposition process of the catalyst with high adhesion of the metal particles to the surface of the substrate; an exception inorganic component, enveloping metal particles, allows you to release a greater proportion of surface-active atoms and to increase the contact surface of the catalyst.

Use as a coating composition, organosol metal-naphthalene allows you to eliminate pollutants catalyst, since the low-temperature metallization process passes the complete removal of naphthalene (without formation of impurity residues). Terpineol as a component of the organic component in the second composition also does not introduce impurities, fully uletuchivayas during drying and annealing. Dimethylformamide, proposed by the present invention the ratio with terpineol, has peptizyme effect. At its introduction in the ratio of less than 1 wt. including the effect peptization is missing, with an increase of more than 1 wt.h. an additional effect is not observed. The ratio of metal - organic component is made on the basis that the reduced metal is less than 1 wt.h. ukhudshe wt.h. increases the viscosity of the composition and complicated process of applying a catalyst.

The heat applied to the carrier structure in the first embodiment of the method carried out in a range of 90 - 100oC, at a temperature of less than 90oC organosol does not melt, and at a temperature of more than 100oC catalytic coating becomes more porous and uneven, with the inclusion of products of thermolysis. In the second variant of the method, the reducing temperature is less than 100oC increases the drying time (reducing the adaptability of the process), and an increase of more than 120oC reduces the quality of the catalytic coating (non-uniform, bubble) due to intensive evaporation of the organic component. The firing temperature of 350 - 400oC sufficient for optimal results, decreasing deteriorates the workability of the process (increase of time without improving quality).

In General, the method is as follows.

It heated up to 90 - 100oC monolithic ceramic block that you want to put a layer of catalytically active metal, touch otterbine in the form of a rod, is convenient for this configuration, size, solid organosol composition naphthalene - Ag, Au, Pt or Pd is after applying the molten organosol media is maintained at the same temperature for 10 15 min to complete sublimation of naphthalene, after which the medium is heated to 300-400oC and held for 5 to 10 minutes before formation of the metal film.

Example 1. Heated to 90oC ceramic media put solid organosol composition naphthalene - Ag. Organosol is melted and evenly applied to the surface of the carrier. After that, the medium was incubated for 10 min to complete sublimation of naphthalene, after which the medium is heated to 350oC and can withstand before formation of the metal film.

Examples of implementation of the proposed method with different ultrafine metals and their alloy are summarized in table 1.

For the implementation of the second variant of the method for obtaining the composition of ultrafine metal - organic component in the liquid state in the form of Hydrosol, solid organosol naphthalene - Ag, Au, Pt, Pd or their alloys is shaken out three times naphthalene twenty-fold by weight, the amount of ethanol or acetone, after decanting, the last portion of solvent to loose draught add terpineol and dimethylformamide in the ratio of 250 : 1 by weight.h., the ratio of metal - organic component of the stand 1 : 50 wt.h. The obtained liquid composition 10 - 20 min treated IU anatoy temperature, then heated to 100 to 120oC to remove solvent, followed by baking at 350 - 400oC for 5 - 10 min before formation of the metal film.

Examples of specific performance with different ultrafine metals and options temperature regime are summarized in table 2.

The use of the invention allows to reduce the temperature of the process of preparation of the catalyst in 2 times, which gives the possibility to reduce energy costs and simplifying used heating equipment. Increasing the surface contact of the catalyst in comparison with the prototype allows to reduce the amount of damage an expensive metal to achieve the desired conversion of gas.

High adhesion of the metal to the surface reduces the mechanical entrainment of the particles and increases the service life of the catalyst.

The proposed methods of application of the catalyst (liquid and solid) are a versatile tool and allow you to cover any configuration of media, including hard-to-reach places, the internal channels allow the use of drip method of application, and the application of the composition of the brush by dipping, etc. will find The S="ptx2">

1. The method of applying a catalyst on the ceramic carrier, comprising coating the surface of the carrier composition containing dispersed platinum group metal in the organic component, followed by heating and annealing, characterized in that the composition is applied to the preheated carrier, as applied composition using ultrafine metal deposited on the naphthalene used as the organic component, the ultrafine metal has additionally also use silver, gold or alloys of the above metals.

2. The method according to p. 1, characterized in that before applying the composition of the ceramic carrier is heated to 90 - 100oC, the heat applied to the carrier of the composition is carried out at the same temperature, and the subsequent firing - at 350 - 400oC.

 

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