EP0262962A2
Expired / Lapsed
EP
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Catalyst for purifying motor vehicle exhaust gases and process for production thereof
Assignee: BASF Catalysts LLC
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Filing: 1987-09-30
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Granted: —
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Expires: 2007-09-30
Abstract
Abstract A catalyst, and a method for producing the catalyst, and a method for purifying exhaust gases which is very efficient in its use of rhodium has a layered catalytic structure on a refractory substrate, the inner layer containing ceria and platinum, the outer layer containing zirconia and rhodium.
Inventors
- 👤 Tadao Numazu Factory Chiba
- 👤 Masaki Numazu Factory Funabiki
- 👤 Tsunao Numazu Factory Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 13:13
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; B01J35/00; B01J35/50; B01J35/56; B01J35/60; B01J35/61; B01J37/00; B01J37/02; B01J37/024; B01J37/0244; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
90 words
A catalyst for purifying exhaust gases essentially comprising a substantially catalytically inert, refractory monolithic support, an inside layer containing a catalytically active refractory oxide formed on the support, and an outside layer containing a catalytically active refractory oxide formed on the inside layer, characterized in that the inside layer contains cerium oxide and platinum and has a weight of 10 to 200g per litre of the catalyst, and the outside layer contains a zirconium compound and rhodium and has a weight of 5 to 60g per litre of the catalyst.
Claim 2
Dependent Claim
90 words
A catalyst for purifying exhaust gases essentially comprising a substantially catalytically inert, refractory monolithic support, an inside layer containing a catalytically active refractory oxide formed on the support, and an outside layer containing a catalytically active refractory oxide formed on the inside layer, characterized in that the inside layer contains cerium oxide and platinum and has a weight of 10 to 200g per litre of the catalyst, and the outside layer contains a zirconium compound and rhodium and has a weight of 5 to 60g per litre of the catalyst.
Claim 3
Dependent Claim
64 words
The catalyst set forth in claim 1 wherein the support has continuous longitudinal unobstructed flow channels each extending through the support and defined by a thin wall, the inside layer is deposited on the walls of the channels, and the catalytically active refractory oxide of one or both layers is finely divided and has a specific surface area of at least about 10 m²/g.
Claim 4
Dependent Claim
34 words
The catalyst set forth in claim 1 or claim 2 wherein the inside layer has a thickness of 5 to 110 microns, and the outside layer has a thickness of 3 to 5 microns.
Claim 5
Dependent Claim
17 words
The catalyst set forth in any preceding claim wherein the catalytically active refractory oxide is active alumina.
Claim 6
Dependent Claim
19 words
The catalyst set forth in any one of claims 1 to 4 wherein the support is composed of cordierite.
Claim 7
Dependent Claim
19 words
The catalyst set forth in any one of claims 1 to 4 wherein the support is composed of metal.
Claim 8
Dependent Claim
32 words
The catalyst set forth in any one of claims 1 to 6 wherein the weight of cerium oxide is 15 to 40% by weight based on the weight of the inside layer.
Claim 9
Dependent Claim
31 words
The catalyst set forth in any one of claims 1 to 7 wherein the weight of platinum is 0.1 to 3.5% by weight based on the weight of the inside layer.
Claim 10
Dependent Claim
19 words
The catalyst set forth in any one of claims 1 to 8 wherein the zirconium compound is zirconium oxide.
Claim 11
Dependent Claim
33 words
The catalyst set forth in any one of claims 1 to 9 wherein the weight of the zirconium compound is 10 to 30% by weight based on the weight of the outside layer.
Claim 12
Dependent Claim
31 words
The catalyst set forth in any one of claims 1 to 9 wherein the weight of rhodium is 0.05 to 2.00% by weight based on the weight of the outside layer.
Claim 13
Dependent Claim
86 words
A process for producing a catalyst according to any preceding claim which comprises depositing a slurry containing a finely divided catalytically active refractory oxide and/or its precursor, cerium oxide or another cerium compound, and platinum or a platinum compound on a substantially catalytically inert refractory monolithic support, thereafter depositing a slurry containing a finely divided catalytically active refractory oxide and/or its precursor, zirconium oxide or another zirconium compound and rhodium or a rhodium compound on the support, and calcining the support having the slurries deposited thereon.
Claim 14
Dependent Claim
17 words
The process set forth in claim 12 wherein the platinum compound in the slurry is platinum hydroxide.
Claim 15
Dependent Claim
20 words
The process set forth in claim 12 or claim 13 wherein the rhodium compound in the slurry is rhodium nitrate.
Claim 16
Dependent Claim
22 words
The process set forth in any one of claims 12 to 14 wherein the zirconium compound in the slurry is zirconyl acetate.
References Cited (Backward Citations)
No citation records indexed.
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