EP0428752A1
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EP
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Exhaust gas purifying catalyst excellent in thermal resistance and method of production thereof
Assignee: NE Chemcat Corp
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Filing: 1990-06-08
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Granted: —
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Expires: 2010-06-08
Abstract
Abstract A catalyst which is used for purifying exhaust gas of an internal-combustion engine of an automobile or the like and can exhibit an excellent performance of purification even after a prolonged, high-temperature service. The catalyst is composed of at least two catalytic component layers carried on a monolithic support, wherein the inner layer contains a catalytic component comprising at least one platinum group element, activated alumina and cerium oxide, while the outer layer at least one platinum group element, activated alumina and optionally a zirconium compound, and at least one of the inner and outer layers also contains a coprecipitated oxide of zirconium stabilized by cerium. This catalyst is produced by preparing activated alumina containing at least one platinum group element, adding other catalytic components thereto to prepare a slurry for each of the inner and outer layers, applying the slurry for the inner layer to a monolithic support followed by firing, and further applying the slurry for the outer layer to the inner layer, followed by firing.
Inventors
- 👤 Masaki 18-25-701 Ichiban-Cho Funabiki
- 👤 Kunihide 818-1 Hara Kayano
- 👤 Teiji Yamada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:40
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01J; B01J23/00; B01J23/38; B01J23/54; B01J23/56; B01J23/63; B01J37/00; B01J37/02; B01J37/0215; B01J37/024; B01J37/0244; B01J37/03; B01D2255/00; B01D2255/90; B01D2255/902; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
87 words
An exhaust gas-purifying catalyst which has a structure to have at least two catalyst component-containing layers on a support having a monolithic structure, and wherein, as the catalyst components, the inner catalyst component-containing layer contains at least one element of the platinum group, activated alumina and cerium oxide, the outer catalyst component-containing layer contains at least one element of the platinum group and activated alumina, and at least one of the inner catalyst component-containing layer and the outer catalyst component-contianing layer further contains a coprecipitated ceria-stabilized zirconia.
Claim 2
Dependent Claim
69 words
An exhaust gas-purifying catalyst which has a structure to have at least two catalyst component-containing layers on a support having monolithic structure, and wherein, as the catalyst components, the inner catalyst component-containing layer contains at least one element of the platinum group, activated alumina and cerium oxide, and the outer catalyst component-containing layer contains at least one element of the platinum group, activated alumina and a coprecipitated ceria-stabilized zirconia.
Claim 3
Dependent Claim
18 words
The exhaust gas-purifying catalyst of claim 1 wherein the inner catalyst component-containig layer contains the coprecipitated ceria-stabilized zirconia.
Claim 4
Dependent Claim
25 words
The exhaust gas-purifying catalyst of claim 1 wherein both the inner catalyst component-containig layer and the outer catalyst component-containig layer contain the coprecipitated ceria-stabilized zirconia.
Claim 5
Dependent Claim
48 words
The exhaust gas-purifying catalyst of any one of claims 1 to 4 wherein the inner catalyst component-containig layer contains platinum as the at least one element of the platinum group and the outer catalyst component-containig layer contains rhodium as the at least one element of the platinum group.
Claim 6
Dependent Claim
32 words
The exhaust gas-purifying catalyst of claim 5 wherein the coprecipitated ceria-stabilized zirconia contains 1 to 25 % by weight of cerium oxide and 99 to 75 % by weight of zirconium oxide.
Claim 7
Dependent Claim
32 words
The exhaust gas-purifying catalyst of claim 5 wherein the coprecipitated ceria-stabilized zirconia contains 5 to 15 % by weight of cerium oxide and 95 to 85 % by weight of zirconium oxide.
Claim 8
Dependent Claim
161 words
A process for preparation of the exhaust gas-purifying catalyst of claim 1 which comprises (a) a step to prepare activated alumina containing at least one element of the platinum group, (b) a step to preapre a slurry 1 containing the prepared platinum group element-containing activated alumina and at least cerium oxide, (c) a step to make the slurry 1 coat onto the support having a monolithic structure and calcine it to form the inner catalyst component-containing layer, (d) a step to prepare activated alumina containing at least one element of the platinum group, (e) a step to preapre a slurry 2 containing the prepared platinum group element-containing activated alumina, and (f) a step to make the slurry 2 prepared in the step of (e) coat onto the catalyst prepared in the step of (c) and calcine it to form the outer catalyst component-containing layer, provided that at least one of the above slurries 1 and 2 contains the coprecipitated ceria-stabilized zirconia.
Claim 9
Dependent Claim
32 words
The process for preparation of the exhaust gas-purifying catalyst of claim 8 wherein the slurry 1 does not contain the coprecipitated ceria-stabilized zirconia and the slurry 2 contains the coprecipitated ceria-stabilized zirconia.
Claim 10
Dependent Claim
32 words
The process for preparation of the exhaust gas-purifying catalyst of claim 8 wherein the slurry 1 contains the coprecipitated ceria-stabilized zirconia and the slurry 2 does not contain the coprecipitated ceria-stabilized zirconia.
Claim 11
Dependent Claim
24 words
The process for preparation of the exhaust gas-purifying catalyst of claim 8 wherein both the slurries 1 and 2 contain the coprecipitated ceria-stabilized zirconia.
Claim 12
Dependent Claim
24 words
The exhaust gas-purifying catalyst of any one of claims 8 to 11 wherein the slurry 1 contains platinum and the slurry 2 contains rhodium.
Claim 13
Dependent Claim
37 words
The process for preparation of the exhaust gas-purifying catalyst of claim 12 wherein the coprecipitated ceria-stabilized zirconia contains 1 to 25 % by weight of cerium oxide and 99 to 75 % by weight of zirconium oxide.
Claim 14
Dependent Claim
37 words
The process for preparation of the exhaust gas-purifying catalyst of claim 12 wherein the coprecipitated ceria-stabilized zirconia contains 5 to 15 % by weight of cerium oxide and 95 to 85 % by weight of zirconium oxide.
Claim 15
Dependent Claim
90 words
An exhaust gas-purifying catalyst which has a structure to have at least two catalyst component-containing layers on a support having a monolithic structure, and wherein, as the catalyst components, the inner catalyst component-containing layer contains at least one element of the platinum group, activated alumina and cerium oxide, the outer catalyst component-containing layer contains at least one element of the platinum group, activated alumina and a zirconium compound, and at least one of the inner catalyst component-containing layer and the outer catalyst component-containing layer further contains a coprecipitated ceria-stabilized zirconia.
Claim 16
Dependent Claim
68 words
An exhaust gas-purifying catalyst which has at least two catalyst component-containing layers on a support having a monolithic structure, and wherein, as the catalytic components, the inner catalyst component-containing layer contains at least one element of the platinum group, activated alumina and cerium oxide and the outer catalyst component-containing layer contains at least one element of the platinum group, activated alumina, coprecipitated ceria-stabilized zirconia and a zirconium compound.
Claim 17
Dependent Claim
18 words
The exhaust gas-purifying catalyst of claim 15 wherein the inner catalyst component-containig layer contains the coprecipitated ceria-stabilized zirconia.
Claim 18
Dependent Claim
25 words
The exhaust gas-purifying catalyst of claim 15 wherein both the inner catalyst component-containig layer and the outer catalyst component-containing layer contain the coprecipitated ceria-stabilized zirconia.
Claim 19
Dependent Claim
48 words
The exhaust gas-purifying catalyst of any one of claims 15 to 18 wherein the inner catalyst component-containig layer contains platinum as the at least one element of the platinum group and the outer catalyst component-containing layer contains rhodium as the at least one element of the platinum group.
Claim 20
Dependent Claim
32 words
The exhaust gas-purifying catalyst of claim 19 wherein the coprecipitated ceria-stabilized zirconia contains 1 to 25 % by weight of cerium oxide and 99 to 75 % by weight of zirconium oxide.
Claim 21
Dependent Claim
32 words
The exhaust gas-purifying catalyst of claim 19 wherein the coprecipitated ceria-stabilized zirconia contains 5 to 15 % by weight of cerium oxide and 95 to 85 % by weight of zirconium oxide.
Claim 22
Dependent Claim
164 words
A process for preparation of the exhaust gas-purifying catalyst of claim 15 which comprises (a) a step to prepare activated alumina containing at least one element of the platinum group, (b) a step to preapre a slurry 1 containing the prepared platinum group element-containing activated alumina and at least cerium oxide, (c) a step to make the slurry 1 coat onto the support having a monolithic structure and calcine it to form the inner catalyst component-containing layer, (d) a step to prepare activated alumina containing at least one element of the platinum group, (e) a step to preapre a slurry 2 containing the prepared platinum group element-containing activated alumina and a zirconium compound, and (f) a step to make the slurry 2 prepared in the step of (e) coat onto the catalyst prepared in the step of (c) and calcine it to form the outer catalyst component-containing layer, provided that at least one of the slurries 1 nad 2 contains the coprecipitated ceria-stabilized zirconia.
Claim 23
Dependent Claim
32 words
The process for preparation of the exhaust gas-purifying catalyst of claim 22 wherein the slurry 1 does not contain the coprecipitated ceria-stabilized zirconia and the slurry 2 contains the coprecipitated ceria-stabilized zirconia.
Claim 24
Dependent Claim
32 words
The process for preparation of the exhaust gas-purifying catalyst of claim 22 wherein the slurry 1 contains the coprecipitated ceriam-stabilized zirconia and the slurry 2 does not contain the coprecipitated ceria-stabilized zirconia.
Claim 25
Dependent Claim
24 words
The process for preparation of the exhaust gas-purifying catalyst of claim 22 wherein both the slurries 1 and 2 contain the coprecipitated ceria-stabilized zirconia.
Claim 26
Dependent Claim
24 words
The exhaust gas-purifying catalyst of any one of claims 22 to 25 wherein the slurry 1 contains platinum and the slurry 2 contains rhodium.
Claim 27
Dependent Claim
37 words
The process for preparation of the exhaust gas-purifying catalyst of claim 26 wherein the coprecipitated ceria-stabilized zirconia contains 1 to 25 % by weight of cerium oxide and 99 to 75 % by weight of zirconium oxide.
Claim 28
Dependent Claim
37 words
The process for preparation of the exhaust gas-purifying catalyst of claim 26 wherein the coprecipitated ceria-stabilized zirconia contains 5 to 15 % by weight of cerium oxide and 95 to 85 % by weight of zirconium oxide.
References Cited (Backward Citations)
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