JP3340268B2 - Method for producing exhaust gas purifying catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a nitrogen oxides contained in the exhaust gas of an automobile engine (hereinafter, referred to as NOx) process for the preparation of catalysts to reduce. More particularly to a method for manufacturing a catalyze for purifying exhaust gas.

[0002]

2. Description of the Related Art A copper ion exchanged zeolite catalyst is known as a monolith catalyst for reducing NOx of this type.
When oxygen and hydrocarbons are present on this copper ion exchanged zeolite catalyst, N
The selective reduction of Ox proceeds catalytically with high efficiency, making it possible to purify exhaust gas from diesel engines, lean-burn gasoline engines, and the like. This copper ion exchanged zeolite catalyst is N
It is a substance obtained by ion-exchanging Na ions of a type ZSM-5 zeolite with Cu ions. Conventionally, a copper ion exchanged zeolite catalyst is constituted by coating a surface of a monolithic carrier made of ceramics such as cordierite with Cu-ZSM-5 zeolite.

[0003]

However, the above-mentioned conventional copper ion exchanged zeolite catalyst has a high NOx selective reduction function, but, on the molecular structure, adsorbs water when water is present, and selects NOx when water is adsorbed. There was a problem that the reduction function was reduced.

[0004] It is an object of the present invention,
By supplying a reducing agent such as light oil, it is to provide a method for producing a stable and high efficiency catalyst for purifying exhaust gas capable of reducing the NOx contained in the exhaust gas at medium.

[0005]

Manufacturing method of the first exhaust gas purifying catalyst SUMMARY OF THE INVENTION TECHNICAL FIELD The present invention of the exhaust gas purifying catalyst, sodium silicate, water-soluble zirconium salt, water-soluble aluminum salt and a water-soluble titanium salt selected and from the group consisting of
Dissolving two or three or more compounds containing the water-soluble aluminum in water or a basic aqueous solution at a predetermined ratio to form a hydroxide, and drying and calcining the hydroxide to produce a composite oxide powder Obtaining a mixed oxide powder, a binder, and water to prepare a slurry, a step of immersing the monolith carrier made of ceramics or metal in the slurry, and drying and firing the monolith carrier immersed in the slurry. And Pt, Pd or R
h. A method comprising the steps of: dipping any of the metal salt aqueous solutions in h, and drying and baking the dipped material in a reducing atmosphere, wherein the water-soluble aluminum salt is aluminum nitrate or aluminum acetate. Method for producing the second exhaust gas purifying catalyst of the present invention, sodium silicate, water-soluble zirconium salt is selected from the group consisting of water-soluble aluminum salt and a water-soluble titanium salt and said water-soluble aluminum
Generating a hydroxide dissolved in water or a basic aqueous solution of two or more compounds at a predetermined ratio including arm,
A step of drying and calcining the hydroxide to obtain a composite oxide powder; a step of kneading the composite oxide powder, a binder and water; a step of forming the kneaded product into a predetermined shape; and a drying of the formed product And sintering, and sintering the molded body to Pt,
A method comprising immersing in a metal salt aqueous solution of either Pd or Rh and drying the immersion and firing in a reducing atmosphere, wherein the water-soluble aluminum salt is aluminum nitrate or aluminum acetate. is there. The water-soluble zirconium salt in the first and second production methods is preferably zirconium nitrate, and the water-soluble titanium salt is preferably titanium chloride.

In the first production method of the present invention, a slurry for wash coating is prepared using the obtained composite oxide powder, and the slurry is coated on the surface of a known ceramic or metal monolith carrier. One or more metals of Pt, Pd and Rh are supported on the coating layer. A ceramic monolith carrier is exemplified by a honeycomb-shaped carrier made of cordierite, alumina or the like, and a metal monolith carrier is exemplified by a carrier made of an Fe-Cr-Al alloy. The metal carrier is formed into a tubular shape after alternately stacking corrugated metal foils and flat metal foils. The slurry is prepared by mixing the composite oxide powder, a binder such as silica sol, and water. After sufficiently immersing the monolith carrier in the slurry, the monolith carrier immersed in the slurry is dried under atmospheric pressure, and
Bake at 1000 ° C. for 1 to 10 hours. Next, the calcined monolithic carrier is immersed in a noble metal salt aqueous solution such as an aqueous chloroplatinic acid solution, an aqueous dinitrodiaminoplatinum solution, an aqueous palladium chloride solution or an aqueous rhodium chloride solution, and dried. 500-10
Bake at 00 ° C for 1 to 3 hours. The content of the noble metal of Pt, Pd or Rh in the noble metal salt aqueous solution or the concentration of the aqueous solution is determined so that the noble metal is supported on the catalyst after calcination in the range of 0.01 to 5% by weight. The loading amount is preferably from 0.1 to 3% by weight, more preferably from 1 to 2% by weight. In the second production method of the present invention, the compact is formed into a pellet, which is fired, and the sintered body is supported with the above-mentioned noble metal of Pt, Pd or Rh.

The third method for producing an exhaust gas purifying catalyst of the present invention comprises mixing two or more alkoxides selected from the group consisting of silicon alkoxides, zirconium alkoxides, aluminum alkoxides and titanium alkoxides at a predetermined ratio. , A step of hydrolyzing the mixture, a step of drying the hydrolysis product and calcining to obtain a composite oxide powder, and a step of mixing the composite oxide powder, a binder and water to prepare a slurry. And a step of immersing the monolithic carrier made of ceramics or metal in the slurry, a step of drying and firing the monolithic carrier immersed in the slurry, and the step of drying the fired monolithic carrier with an aqueous solution of a metal salt of Co, Cu, Ni or Fe Immersion, drying and sintering of the immersion material, and immersing the immersion material in a monolithic carrier of Pt, Pd or Immersing any of the metal salt aqueous solution of Rh, the method comprising the step of firing in a dry reducing atmosphere immersion thereof.

The mixing of the alkoxide before hydrolysis in the third production method is preferably performed in an organic solvent. This is to promote mixing and to make the composition of the precipitate generated by hydrolysis uniform. As the organic solvent, benzene, alcohol, toluene, xylene and the like are suitable. The temperature at which the alkoxide is mixed may be any temperature as long as it is lower than the temperature at which each component alkoxide decomposes.
0-80 ° C is particularly desirable.

The hydrolysis of the above mixture is performed by adding decarbonated distilled water to the reaction solution. The temperature at the time of hydrolysis is preferably from 0 to 100 ° C, in which the alkoxide of each component is not decomposed and easy to handle, and particularly preferably from 25 to 80 ° C. This hydrolysis produces a powdery white precipitate. If the precipitate is separated from the hydrolyzate by centrifugation or filtration, and if necessary dried such as vacuum drying,
A powder is obtained. In the state of the hydrolysis product as it is, it is an amorphous composite oxide in many cases, but easily becomes a crystalline composite oxide by calcination. This calcination temperature is preferably 600 ° C. or higher and lower than the decomposition start temperature of the composite oxide in order to improve the efficiency of transition to crystalline.
Further, it can be obtained at a low temperature or by vacuum heating. As a result of chemical analysis, the composite oxide obtained by calcination
It is a high-purity substance having an impurity of 0.1% by weight or less, and has a specific surface area of 10 to 400 m ² / g and is a very active fine particle having a submicron particle size. A slurry is prepared by mixing the above-mentioned composite oxide powder, a binder and water, and a monolith carrier made of ceramics or metal is immersed in the slurry and dried and fired to obtain a monolith carrier having a composite oxide layer.

[0010] The calcined monolithic carrier is an aqueous solution of copper nitrate,
Copper acetate aqueous solution, cobalt nitrate aqueous solution, cobalt acetate aqueous solution, nickel nitrate aqueous solution, nickel acetate aqueous solution, immersed in a transition metal salt aqueous solution such as iron nitrate aqueous solution or iron acetate aqueous solution, and dried, the immersed under atmospheric pressure, 500-7
Bake at 00 ° C for 1 to 3 hours. The calcined monolithic carrier is immersed in a noble metal salt aqueous solution such as an aqueous chloroplatinic acid solution, an aqueous dinitrodiaminoplatinum solution, an aqueous palladium chloride solution or an aqueous rhodium chloride solution, and dried. 1-3 at ~ 700 ° C
Bake for hours. The Co, C in the transition metal salt aqueous solution
The content of the transition metal of u, Ni or Fe or the concentration of the aqueous solution is determined so that the transition metal is added to the fired catalyst in the range of 0.05 to 5% by weight. It is preferably from 0.1 to 2% by weight, more preferably from 0.5 to 1% by weight. Further, the Pt,
The content of the noble metal of Pd or Rh or the concentration of the aqueous solution is determined so that the noble metal is supported on the fired catalyst in the range of 0.01 to 5% by weight.
The content is preferably 1 to 3% by weight, more preferably 1 to 2% by weight.

In a fourth method for producing a catalyst for purifying exhaust gas of the present invention, two or three alkoxides selected from the group consisting of silicon alkoxide, zirconium alkoxide, aluminum alkoxide and titanium alkoxide are mixed at a predetermined ratio. A step of hydrolyzing the mixture, a step of drying the hydrolysis product and calcining to obtain a composite oxide powder, a step of kneading the composite oxide powder, a binder and water, and A step of drying and firing the molded article; a step of immersing the sintered body obtained by firing the molded article in an aqueous solution of a metal salt of Co, Cu, Ni or Fe; A step of drying and firing, a step of immersing the sintered body obtained by firing the immersion in an aqueous solution of a metal salt of Pt, Pd or Rh, and a step of drying the immersion and firing in a reducing atmosphere. The method comprising the door. In the fourth manufacturing method, the compact is formed into a pellet, which is baked into a pellet, and then a Pt, Pd, or R is added to a pellet obtained by adding a metal of Co, Cu, Ni, or Fe to the pellet.
h noble metal can be supported.

[0012] The fifth method for producing an exhaust gas purifying catalyst of the present invention is a method for producing H-Co-silicate, H-Ga-silicate,
A step of kneading one or more metallosilicate powders selected from the group consisting of H-In-silicate and H-Fe-silicate, a binder and water, and a step of molding the kneaded product into a predetermined shape; A step of drying and firing the molded article; a step of dipping the sintered body obtained by firing the molded article in an aqueous solution of a metal salt of Pt, Pd or Rh; a step of drying and firing the dipped article; Co, C
This is a method including a step of immersing in a metal salt aqueous solution of any one of u, Ni and Fe, and a step of drying the immersion and firing it in a reducing atmosphere. The sixth method for producing an exhaust gas purifying catalyst of the present invention is characterized in that one or two kinds selected from the group consisting of H-Co-silicate, H-Ga-silicate, H-In-silicate and H-Fe-silicate A step of preparing a slurry by mixing the above metallosilicate powder, binder and water, a step of immersing the monolith carrier made of ceramics or metal in the slurry, and a step of drying and firing the monolith carrier immersed in the slurry, A step of immersing the fired monolithic carrier in an aqueous solution of a metal salt of either Pt, Pd, or Rh; a step of drying and sintering the immersed material;
And a step of drying the immersion and firing it in a reducing atmosphere.

In any of the first to sixth production methods of the present invention, examples of the binder include one or more binders selected from the group consisting of kaolin, talc, aluminum hydroxide, silica sol and the like. As molding aids, polyvinyl alcohol (PVA), propylene glycol, methyl cellulose (MC), carboxymethyl cellulose (CMC), polyethylene glycol (PE
One or more molding aids selected from the group consisting of G) and the like. The kneading is performed by a kneader so that each component is uniformly mixed.

Further, in the fifth production method of the present invention, the solid content of the kneaded material is reduced to 10% in order to enhance the moldability and the strength of the molded body.
When the weight is 0% by weight, the kneaded material is 70% metallosilicate.
It is preferable to contain the binder in an amount of up to 90% by weight and the binder in an amount of 20 to 30% by weight. In the case of a monolithic catalyst, the molding of the kneaded material is performed using an extruder so that the molded body has a honeycomb shape in which a large number of regular through holes such as squares, triangles, and hexagons are formed in the flow direction of the exhaust gas. . The molded body is dried under atmospheric pressure and then at atmospheric pressure at 500 to 800 ° C. for 1 to 5 times.
Fired for hours. In the case of a pellet catalyst, it is formed into a pellet and fired in the same manner as described above.

The sintered body is immersed in an aqueous solution of a transition metal salt such as an aqueous solution of cobalt nitrate, an aqueous solution of cobalt acetate, an aqueous solution of copper nitrate, an aqueous solution of iron nitrate or an aqueous solution of nickel nitrate. , Ni or F
e. Pt, Pd or Rh is supported by immersing in a noble metal salt aqueous solution such as an aqueous chloroplatinic acid solution, an aqueous dinitrodiaminoplatinum solution, an aqueous palladium chloride solution or an aqueous rhodium chloride solution, and drying and subjecting the immersion to reduction firing. The content of the noble metal of Pt, Pd or Rh in the noble metal salt aqueous solution or the concentration of the aqueous solution is determined so that the noble metal is supported on the catalyst after calcination in the range of 0.01 to 5% by weight. The loading amount is preferably from 0.1 to 3% by weight, more preferably from 1 to 2% by weight. The content of the transition metal of Co, Cu, Ni or Fe in the aqueous solution of the transition metal salt or the concentration of the aqueous solution is such that the transition metal is added to the fired catalyst in a range of 0.05 to 5% by weight. The addition amount is preferably 0.1 to 2% by weight,
0.5 to 1% by weight is more preferred.

[0016]

In the catalyst produced by the first or second method , S
_{iO 2, Al 2 O 3,} 2 kinds selected from the group consisting of TiO ₂ and ZrO ₂ or 3 or more kinds of composite oxide has a relatively large amount of solid acid, Pt on the surface of the composite oxide, Pd Or R
The catalyst loaded with h promotes hydrocarbon cracking because the amount of solid acid that activates the catalyst is increased,
NOx can be reduced with high efficiency in the presence of NO, hydrocarbons and oxygen. Further, even in the presence of water, the change in the catalyst is small and the NOx contained in the exhaust gas can be reduced with high efficiency. Co, Cu, N are added to the catalyst produced by the first method.
By including a small amount of i or Fe, the amount of solid acid present on the surface of the support increases, and the activation of the catalyst is promoted. Therefore, NOx can be reduced with high efficiency in the presence of NO, hydrocarbons and oxygen. . In the catalyst manufactured by the fifth or sixth method , the monolithic carrier itself is a sintered body containing a trace amount of Co, Cu, Ni or Fe obtained by sintering metallosilicate at a relatively high temperature, and Since Pt, Pd or Rh is supported, NOx contained in the exhaust gas can be reduced with high efficiency with little change in the catalyst even in the presence of water.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following examples. <Example 1> An aqueous solution in which 21.3 g of aluminum nitrate powder was dissolved in water and an aqueous solution in which 33.9 g of zirconium nitrate powder were dissolved in water were mixed, and 1% aqueous ammonia was gradually added dropwise while stirring uniformly. To form a precipitate of these mixed reaction products. The precipitated product was removed by filtration, washed with water, dried, and calcined at 700 ° C. for 3 hours to form Al ₂ O ₃ and Z
A composite oxide powder containing rO ₂ was obtained. This powder had a high purity and a specific surface area of 120 m ² / g.

The obtained composite oxide powder, silica sol and water were uniformly mixed to prepare a washcoat slurry. As shown in FIG. 1, after a honeycomb-shaped monolithic carrier 11 made of cordierite was sufficiently immersed in the slurry, the monolithic carrier 11 immersed in the slurry was dried and calcined at 600 ° C. under atmospheric pressure for 3 hours. . The composite oxide layer 12 was formed on the surface of the monolithic carrier 11.
Next, the monolithic carrier 1 on which the composite oxide layer 12 is formed
1 is immersed in an aqueous solution of chloroplatinic acid (2% chloroplatinic acid) and dried, and the immersed product is calcined at 500 ° C. under atmospheric pressure for 3 hours in a reducing atmosphere, for example, hydrogen gas to obtain a monolithic catalyst 1
0 was obtained. The composite oxide layer 12 supported 1 wt% of Pt.

<Example 2> A silicon ethoxide-ethanol solution (1 as Si component)
0ml / l) 100ml and aluminum ethoxide
Ethanol solution (containing 10 g / l as Al component) 20
Then, water was gradually added dropwise while stirring uniformly, and the mixed reaction product was hydrolyzed at 80 ° C.
The product precipitated by hydrolysis is filtered out, washed with water, dried, and calcined at 800 ° C. for 3 hours to form S
A composite oxide powder of iO ₂ and Al ₂ O ₃ was obtained. This powder had a high purity and a specific surface area of 130 m ² / g.

The obtained composite oxide powder, silica sol and water were uniformly mixed to prepare a washcoat slurry. After sufficiently immersing a honeycomb-shaped monolithic carrier made of cordierite in the slurry, the monolithic carrier immersed in the slurry was dried, and then dried under atmospheric pressure at 700 ° C.
For 3 hours. A composite oxide layer was formed on the surface of the monolithic carrier. Next, the fired monolithic carrier was immersed in an aqueous iron nitrate solution (iron nitrate concentration: 2%), dried, and then fired at 500 ° C. under atmospheric pressure for 1 hour. The monolithic carrier on which the composite oxide layer is formed is immersed in an aqueous chloroplatinic acid solution (chloroplatinic acid concentration: 2%) and dried.
Baking at 0 ° C. for 3 hours. 2% by weight of P in the composite oxide layer
t was carried, and 0.5% by weight of Fe was contained as a promoter component. In addition, the molar ratio of SiO ₂ / Al ₂ O _{3 in} the composite oxide layer was 50/50.

<Example 3> H-Co-silicate powder, kaolin, PVA, silica sol and water were weighed in a weight ratio of 57: 10: 5: 20: 8, and were uniformly kneaded by a kneader. did. The kneaded product was put into an extruder to form a honeycomb-shaped formed body. The formed body was dried and calcined at 600 ° C. under atmospheric pressure for 3 hours to obtain a monolith carrier. Next, the calcined monolithic carrier was subjected to a rhodium nitrate aqueous solution (a rhodium nitrate concentration of 0.1%).
5%), and after drying, the immersed material was placed under atmospheric pressure.
It was baked at 500 ° C. for 3 hours. This calcined monolithic carrier is immersed in a chloroplatinic acid aqueous solution (chloroplatinic acid concentration 2%),
After drying, the immersion was calcined in a reducing atmosphere, for example, hydrogen gas at 500 ° C. for 3 hours to obtain a monolith catalyst. This monolithic carrier supported 1% by weight of Pt, and contained 0.3% by weight of Rh as a promoter component.

<Comparative Example 1> A monolithic carrier composed of cordierite of the same shape and size as the monolithic carrier of Example 1 includes a copper ion exchanged zeolite obtained by ion exchange of Na ions of Na type ZSM-5 zeolite with Cu ions. After being immersed in the slurry for washcoat and dried, it was calcined at 500 ° C. under atmospheric pressure for 3 hours to obtain a monolith catalyst.

<Evaluation Test> With respect to the monolithic catalysts of Examples 1 to 3 and Comparative Example 1, a part of the exhaust gas of the following diesel engine was introduced into a catalyst reaction tube to perform a NOx reduction reaction, and the NOx reduction rate was determined. Examined. The test gas contained 1000 ppm of NO and 10 ppm of HC.
0 ppm, 10 ppm SO ₂ , 10% O ₂ , and H ₂
Light oil was added as a reducing agent to the engine exhaust gas containing 6% of O at a ratio of (light oil / NO) = 2. The test gas was 150 ° C, 200 ° C, 250 ° C, 30
The temperature is controlled at 0 ° C., 350 ° C., 400 ° C. and 450 ° C., and the NOx reduction rate at each temperature is 2
It was measured at a space velocity (SV) of 0000 hr ^-1 . The result is shown in FIG. The NOx reduction rate was determined by the following equation, where the NO concentration before passing through the monolith catalyst was C ₁ and the NO concentration after passing was C ₂ . NOx reduction rate = {(C ₁ −C ₂ ) / C ₁ } × 100 (%) (1) As is clear from FIG. 2, since the test gas contained 5% of H ₂ O, the test gas of Comparative Example 1 was used. The NOx reduction rates of the catalysts of Examples 1, 2 and 3 at 250 ° C. are about 39%, about 32% and about 18%, respectively, while the NOx reduction rate of the monolith catalyst is 16% at 400 ° C. Values at 450 ° C. of about 15%, about 14% and about 15%, respectively. In particular, the NOx reduction rate of the monolithic catalyst of Comparative Example 1 decreased relatively early with the passage of time, whereas the monolithic catalysts of Examples 1 to 3 maintained substantially the same NOx reduction rate over a long period of time. .

[0024]

As described above, according to the present invention, S
a pellet support formed of two or more composite oxides selected from the group consisting of iO ₂ , Al ₂ O ₃ , TiO ₂ and ZrO ₂ , or a ceramic support coated with the composite oxide layer, or The metal carrier contains a relatively large amount of solid acid. Since the catalyst produced by the first or second method of the present invention supports Pt, Pd or Rh on the surface of the composite oxide acting as a solid acid catalyst, NO and hydrocarbon NOx can be efficiently reduced in the presence of oxygen and oxygen. In addition, even in the presence of water, there is an excellent effect of reducing the amount of NOx contained in the exhaust gas with little change in the catalyst and high efficiency.

Further, SiO ₂ , Al ₂ O ₃ , TiO ₂ and Z
A monolithic carrier or pellet carrier formed of two or three or more composite oxides selected from the group consisting of rO ₂ , or a ceramic or metal carrier coated with the composite oxide layer, Co, Cu, By including a small amount of Ni or Fe, the solid acid of the composite oxide increases. Since the catalyst produced by the third or fourth method of the present invention has Pt, Pd or Rh supported on the surface of the composite oxide acting as a solid acid catalyst, the catalyst is the same as described above. The effect of is obtained.

Further, one selected from the group consisting of H-Co-silicate, H-Ga-silicate, H-In-silicate and H-Fe-silicate containing a metal of Co, Cu, Ni or Fe as an additive. A catalyst in which Pt, Pd or Rh is supported on a monolithic carrier or pellet carrier obtained by sintering one or more metallosilicates, or Co,
Fifth or Pt, Pd, or Rh supported on a ceramic or metal carrier coated with the metallosilicate layer containing a metal of Cu, Ni or Fe as an additive.
The same effect as described above can be obtained with the catalyst produced by the sixth method .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an exhaust gas purifying catalyst manufactured by a first method of Embodiment 1 of the present invention.

FIG. 2 shows N of catalysts of Examples 1 to 3 and Comparative Example 1 of the present invention.
The figure which shows the change by the catalyst inlet temperature of Ox reduction rate.

[Explanation of symbols]

 Reference Signs List 10 monolith catalyst (catalyst) 11 monolith carrier 12 composite oxide layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-22947 (JP, A) JP-A-4-371231 (JP, A) JP-A-53-146991 (JP, A) JP-A-60-1985 220148 (JP, A) JP-A-62-149339 (JP, A) JP-A-60-61033 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 21/00-37 / 36

Claims (6)

(57) [Claims] 1. A method according to claim 1, wherein two or three or more compounds selected from the group consisting of sodium silicate, a water-soluble zirconium salt, a water-soluble aluminum salt and a water-soluble titanium salt and containing the water-soluble aluminum are mixed in water at a predetermined ratio. Or dissolving in a basic aqueous solution to form a hydroxide; drying the hydroxide and calcining to obtain a composite oxide powder; and mixing the composite oxide powder, a binder and water. A step of preparing a slurry, a step of immersing a monolithic carrier made of ceramics or metal in the slurry, a step of drying and firing the monolithic carrier immersed in the slurry, and the step of drying the fired monolithic carrier of Pt, Pd or Rh. A step of immersing in any metal salt aqueous solution, and a step of drying the immersion and firing in a reducing atmosphere, wherein the water-soluble aluminum salt is nitric acid The method of manufacturing the exhaust gas purifying catalyst, which is a aluminum or aluminum acetate. 2. A method according to claim 1, wherein two or more compounds selected from the group consisting of sodium silicate, a water-soluble zirconium salt, a water-soluble aluminum salt and a water-soluble titanium salt and containing the water-soluble aluminum are mixed in water at a predetermined ratio. Or a step of dissolving in a basic aqueous solution to form a hydroxide; a step of drying and calcination of the hydroxide to obtain a composite oxide powder; and a step of kneading the composite oxide powder, a binder and water. Forming the kneaded product into a predetermined shape; drying and firing the formed product; immersing the sintered body obtained by firing the formed product in an aqueous solution of a metal salt of Pt, Pd or Rh And a step of drying the immersion and firing it in a reducing atmosphere, wherein the water-soluble aluminum salt is aluminum nitrate or aluminum acetate. Method. 3. a step of mixing two or three or more alkoxides selected from the group consisting of silicon alkoxide, zirconium alkoxide, aluminum alkoxide and titanium alkoxide at a predetermined ratio; and hydrolyzing the mixture. Drying the hydrolysis product and calcining to obtain a composite oxide powder; mixing the composite oxide powder, a binder and water to prepare a slurry; and a ceramic or metal monolithic carrier. A step of immersing the monolithic carrier in the slurry; a step of drying and firing the monolithic carrier immersed in the slurry;
Immersing in a metal salt aqueous solution of any one of the above; drying and sintering the immersed material;
h. A method for producing an exhaust gas purifying catalyst, comprising: a step of immersing the catalyst in any one of the aqueous metal salt solutions; and a step of drying the immersion and firing in a reducing atmosphere. 4. a step of mixing at a predetermined ratio two or three or more alkoxides selected from the group consisting of silicon alkoxide, zirconium alkoxide, aluminum alkoxide and titanium alkoxide; and hydrolyzing the mixture; A step of drying and calcining the hydrolysis product to obtain a composite oxide powder, a step of kneading the composite oxide powder, a binder, and water, and a step of molding the kneaded product into a predetermined shape, A step of drying and firing the molded article; and firing the sintered body of the molded article using Co, Cu, Ni or F.
e, a step of drying and sintering the immersed object, and a step of sintering the sintered body obtained by sintering the immersed object in an aqueous solution of a metal salt of Pt, Pd or Rh. A method for producing an exhaust gas purifying catalyst, comprising: a step of drying the immersed material and firing it in a reducing atmosphere. 5. One or more metallosilicate powders selected from the group consisting of H-Co-silicate, H-Ga-silicate, H-In-silicate and H-Fe-silicate, a binder and water. Kneading, kneading the molded product into a predetermined shape, drying and firing the molded product, and sintering the molded product by Co, Cu, Ni or F.
e, a step of drying and sintering the immersed object, and a step of sintering the sintered body obtained by sintering the immersed object in an aqueous solution of a metal salt of Pt, Pd or Rh. A method for producing an exhaust gas purifying catalyst, comprising: a step of drying the immersed material and firing it in a reducing atmosphere. 6. A binder, water and one or more metallosilicate powders selected from the group consisting of H-Co-silicate, H-Ga-silicate, H-In-silicate and H-Fe-silicate. , A step of preparing a slurry by mixing the above, a step of immersing a monolithic carrier made of ceramics or metal in the slurry, a step of drying and firing the monolithic carrier immersed in the slurry, Cu, Ni or Fe
Immersing in a metal salt aqueous solution of any one of the above; drying and sintering the immersed material;
h. A method for producing an exhaust gas purifying catalyst, comprising: a step of immersing the catalyst in any one of the aqueous metal salt solutions; and a step of drying the immersion and firing in a reducing atmosphere. [0001]