EP0272136A2
Expired / Lapsed
EP
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Catalyst for purifying exhaust gas and method for its production
Assignee: Nippon Shokubai Co Ltd
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Filing: 1987-12-18
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Granted: —
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Expires: 2007-12-18
Abstract
Abstract A catalyst for purifying exhaust gas comprises a honeycomb carrier of monolithic structure and a coating layer deposited on the honeycomb carrier and formed with a catalyst composition containing a refractory inorganic oxide in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns, which refractory inorganic oxide has platinum and/or palladium and rhodium deposited thereon in high concentrations. This catalyst is produced by coating the honeycomb carrier with an aqueous slurry containing the catalyst composition and calcining the coated carrier.
Inventors
- 👤 Tomohisa Ohata
- 👤 Kazuo Tsuchitani
- 👤 Eiichi Shiraishi
- 👤 Shinya Kitaguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 10:01
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; B01J37/024; B01J37/0248; B01J35/00; B01J35/50; B01J35/56; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
54 words
A catalyst for purifying exhaust gas comprising a honeycomb carrier of monolithic structure and a coating layer applied on said honeycomb carrier and formed with a catalyst composition comprising a platinum group metal-supporting zirconia produceable by depositing said platinum group metal on zirconia powder, a refractory inorganic oxide, and a rare earth metal oxide.
Claim 2
Dependent Claim
54 words
A catalyst for purifying exhaust gas comprising a honeycomb carrier of monolithic structure and a coating layer applied on said honeycomb carrier and formed with a catalyst composition comprising a platinum group metal-supporting zirconia produceable by depositing said platinum group metal on zirconia powder, a refractory inorganic oxide, and a rare earth metal oxide.
Claim 3
Dependent Claim
58 words
A catalyst according to claim 1, wherein said platinum group metal is at least one member selected from (a) rhodium, (b) combination of rhodium and platinum, (c) combination of rhodium and palladium, and (d) combination of rhodium, platinum, and palladium, and is deposited in proportion in the range of 0.5 to 30% by weight on said zirconia powder.
Claim 4
Dependent Claim
40 words
A catalyst according to claim 1 or 2, wherein said refractory inorganic oxide contains at least one member selected from cerium, lanthanum, and neodymium in proportion in the range of 0.1 to 30% by weight to said refractory inorganic oxide.
Claim 5
Independent Claim
46 words
A method for the production of a catalyst for purifying exhaust gas, which comprises coating a honeycomb carrier of monolithic structure with an aqueous slurry containing a platinum group metal-carrying zirconia, refractory inorganic oxide, and a rare earth metal oxide and calcining the resultant coated carrier.
Claim 6
Independent Claim
46 words
A method for the production of a catalyst for purifying exhaust gas, which comprises coating a honeycomb carrier of monolithic structure with an aqueous slurry containing a platinum group metal-carrying zirconia, refractory inorganic oxide, and a rare earth metal oxide and calcining the resultant coated carrier.
Claim 7
Dependent Claim
138 words
A catalyst for purifying exhaust gas, comprising a honeycomb carrier of monolithic structure and a coating layer applied on said honeycomb carrier and formed with a catalyst composition containing a refractory inorganic oxide in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns, said refractory inorganic oxide being (A) at least one refractory inorganic oxide selected from (a) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from platinum and palladium and (b) a refractory inorganic oxide having 1 to 20% by weight of rhodium deposited thereon or (B) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from platinum and palladium and 1 to 20% by weight of rhodium.
Claim 8
Dependent Claim
138 words
A catalyst for purifying exhaust gas, comprising a honeycomb carrier of monolithic structure and a coating layer applied on said honeycomb carrier and formed with a catalyst composition containing a refractory inorganic oxide in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns, said refractory inorganic oxide being (A) at least one refractory inorganic oxide selected from (a) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from platinum and palladium and (b) a refractory inorganic oxide having 1 to 20% by weight of rhodium deposited thereon or (B) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from platinum and palladium and 1 to 20% by weight of rhodium.
Claim 9
Dependent Claim
20 words
A catalyst according to claim 5, wherein a refractory inorganic oxide having no noble metal deposited thereon is incorporated additionally.
Claim 10
Dependent Claim
33 words
A catalyst according to claim 6, wherein the amount of said refractory inorganic oxide containing no deposited noble metal is in the range of 50 to 200 g per liter of said carrier.
Claim 11
Dependent Claim
41 words
A catalyst according to claim 5, 6 or 7, wherein the refractory inorganic oxide containing no deposited noble metal is at least one member selected from the group consisting of alumina, silica, titania, zirconia, alumina-silica, alumina-titania, alumina-zirconia, silica-titania, silica-zirconia, and alumina-magnesia.
Claim 12
Dependent Claim
24 words
A catalyst according to any one of claims 5 to 8, wherein said refractory inorganic oxide containing no deposited noble metal is activated alumina.
Claim 13
Dependent Claim
23 words
A catalyst according to claim 9, wherein said activated alumina possesses a specific surface area in the range of 5 to 200 m²/g.
Claim 14
Dependent Claim
20 words
A catalyst according to any one of claims 5 to 10, wherein said catalyst composition further incorporates therein cerium oxide.
Claim 15
Dependent Claim
34 words
A catalyst according to claim 11, wherein said cerium oxide is incorporated in said catalyst composition in an amount in the range of 1 to 150 g as CeO₂ per liter of said carrier.
Claim 16
Dependent Claim
94 words
A catalyst according to any one of claims 5 to 12, wherein said catalyst composition contains either (A) the combination of (a) a refractory inorganic oxide having 5 to 30% by weight of platinum deposited thereon and (b) a refractory inorganic oxide having 1 to 20% by weight of rhodium deposited therein or (B) a refractory inorganic oxide having 5 to 30% by weight of platinum and 1 to 20% by weight of rhodium deposited therein in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns.
Claim 17
Dependent Claim
13 words
A catalyst according to claim 13, wherein said refractory inorganic oxide is alumina.
Claim 18
Dependent Claim
118 words
A catalyst according to any one of claims 5 to 12, wherein said catalyst composition contains either (A) at least one zirconia selected from the group consisting of (a) zirconia having deposited thereon 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and (b) zirconia having 1 to 20% by weight of rhodium deposited thereon or (B) zirconia having deposited therein 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and 1 to 20% by weight of rhodium, in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns.
Claim 19
Independent Claim
152 words
A method for the production of a catalyst for purifying exhaust gas, which comprises coating a honeycomb carrier of monolithic structure with an aqueous slurry containing a catalyst composition and subsequently calcining the coated carrier, said catalyst composition containing either (A) at least one refractory inorganic oxide selected from the group consisting of (a) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and (b) a refractory inorganic oxide having 1 to 20% by weight of rhodium deposited therein or (B) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and 1 to 20% by weight of rhodium, in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns.
Claim 20
Independent Claim
152 words
A method for the production of a catalyst for purifying exhaust gas, which comprises coating a honeycomb carrier of monolithic structure with an aqueous slurry containing a catalyst composition and subsequently calcining the coated carrier, said catalyst composition containing either (A) at least one refractory inorganic oxide selected from the group consisting of (a) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and (b) a refractory inorganic oxide having 1 to 20% by weight of rhodium deposited therein or (B) a refractory inorganic oxide having deposited thereon 5 to 30% by weight of at least one noble metal selected from the group consisting of platinum and palladium and 1 to 20% by weight of rhodium, in the form of particles possessing an average particle diameter in the range of 0.5 to 20 microns.
Claim 21
Dependent Claim
22 words
A method according to claim 16, wherein said calcination is carried out at a temperature in the range of 100° to 600°C.
References Cited (Backward Citations)
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