US4294726A
Expired / Lapsed
US
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Catalyst for the purification of exhaust gases of internal combustion engines
Assignee: Evonik Operations GmbH
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Filing: 1980-02-11
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Granted: 1981-10-13
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Expires: 2000-02-11
Abstract
Abstract A three-way catalyst is described for the purification of automobile exhaust gases formed of an active substance of platinum and rhodium and possibly base metal(s) at a certain weight ratio between the two noble metals and at a certain atomic ratio between the noble and the base metal, which are precipitated onto active aluminum oxide containing certain quantities of CeO 2 , ZrO 2 and Fe 2 O 3 , and whereby the catalyst is obtained by impregnating active aluminum oxide, possibly stabilized with alkaline earth metal, with a solution of cerium, zirconium and iron salt which is thereupon calcined in air at 500°-700° C. and then treated after application of an impregnation of salts of the active substance components in a gas current containing hydrogen at temperatures below 650° C.
Inventors
- 👤 Alfred Bozon
- 👤 Edgar Koberstein
- 👤 Hans-Dieter Pletka
- 👤 Herbert Volker
- 👤 Eduard Lakatos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:27
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01J; B01J23/00; B01J23/70; B01J23/89; B01J23/8933; B01J37/00; B01J37/02; B01J37/024; F; F02; F02B; F02B1/00; F02B1/02; F02B1/04; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
177 words
A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum and rhodium containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1; (b) 5-15% by weight of a mixture of CeO 2 and ZrO 2 , whereby these oxides are at weight ratios of 20-80:80-20; (c) 1-10% by weight of Fe 2 O 3 as well as (d) a residual quantity up to 100% by weight of aluminum oxide of the transition series and obtained by impregnating a carrier material of Al 2 O 3 of the transition series, with an aqueous solution containing cerium, zirconium and iron salts or, mixing the carrier material with the respective oxides of cerium, zirconium and iron, tempering for 30-180 minutes in air at 500°-700° C. thereupon impregnating the carrier with an aqueous solution of a salt of platinum and a salt of rhodium, drying and subsequently treating in a gas current containing hydrogen at temperatures 250°-650° C.
Claim 2
Dependent Claim
177 words
A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum and rhodium containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1; (b) 5-15% by weight of a mixture of CeO 2 and ZrO 2 , whereby these oxides are at weight ratios of 20-80:80-20; (c) 1-10% by weight of Fe 2 O 3 as well as (d) a residual quantity up to 100% by weight of aluminum oxide of the transition series and obtained by impregnating a carrier material of Al 2 O 3 of the transition series, with an aqueous solution containing cerium, zirconium and iron salts or, mixing the carrier material with the respective oxides of cerium, zirconium and iron, tempering for 30-180 minutes in air at 500°-700° C. thereupon impregnating the carrier with an aqueous solution of a salt of platinum and a salt of rhodium, drying and subsequently treating in a gas current containing hydrogen at temperatures 250°-650° C.
Claim 3
Dependent Claim
41 words
A catalyst as defined in claim 1 wherein a coating comprising the components (a)-(d) is present on a honeycomb-shaped structural support made of ceramic or metal in a quantity of 5-30% by weight, related to the weight of the structural support.
Claim 4
Dependent Claim
20 words
A catalyst as defined in claim 1 wherein the carrier material is present in the form of molded bulk material.
Claim 5
Dependent Claim
27 words
A catalyst as defined in claim 1 wherein a coating comprising the components (a)-(d) is present on structurally reinforcing bulk material bodies of ceramic or of metal.
Claim 6
Dependent Claim
224 words
A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum, rhodium and at least one of the base metal elements aluminum, titanium, tin, chromium, manganese, cobalt and nickel containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1 and an atomic ratio between the platinum group metals and the base metals which may be present of 1:6-2:1. (b) 5-15% by weight of a mixture of CeO 2 and ZrO 2 , whereby these oxides are at weight ratios of 20-80:80-20; (c) 1-10% by weight of Fe 2 O 3 as well as (d) a residual quantity up to 100% by weight of aluminum oxide of the transition series and obtained by impregnating a carrier material of Al 2 O 3 of the transition series optionally lattice stabilized with an alkaline earth metal, with an aqueous solution containing cerium, zirconium, and iron salts or mixing the carrier material with a mixture of oxides of cerium, zirconium and iron, tempering for 30-180 minutes in air at 500°-700° C. thereupon impregnating the carrier with an aqueous solution of a salt platinum, rhodium and at least one base metal component, drying and subsequently treating in a gas current containing hydrogen at temperatures of 250°-650° C.
Claim 7
Dependent Claim
224 words
A catalyst for simultaneous oxidation of carbon monoxide and hydrocarbons and reduction of nitric oxides in exhaust gases of internal combustion engines, comprising (a) 0.03-3% by weight of a platinum, rhodium and at least one of the base metal elements aluminum, titanium, tin, chromium, manganese, cobalt and nickel containing active phase with a weight ratio between platinum and rhodium of 2:1-20:1 and an atomic ratio between the platinum group metals and the base metals which may be present of 1:6-2:1. (b) 5-15% by weight of a mixture of CeO 2 and ZrO 2 , whereby these oxides are at weight ratios of 20-80:80-20; (c) 1-10% by weight of Fe 2 O 3 as well as (d) a residual quantity up to 100% by weight of aluminum oxide of the transition series and obtained by impregnating a carrier material of Al 2 O 3 of the transition series optionally lattice stabilized with an alkaline earth metal, with an aqueous solution containing cerium, zirconium, and iron salts or mixing the carrier material with a mixture of oxides of cerium, zirconium and iron, tempering for 30-180 minutes in air at 500°-700° C. thereupon impregnating the carrier with an aqueous solution of a salt platinum, rhodium and at least one base metal component, drying and subsequently treating in a gas current containing hydrogen at temperatures of 250°-650° C.
Claim 8
Dependent Claim
33 words
A catalyst as defined in claim 5, wherein the base metal is aluminum or nickel, and platinum group metals and aluminum or nickel are present in a weight ratio of 3:1-1:1 or 4:1-2:1.
Claim 9
Dependent Claim
43 words
A catalyst as defined in claims 5 and 6 wherein a coating comprising the components (a)-(d) is present on a honeycomb-shaped structural reinforcer made of ceramic or matal in a quantity of 5-30% by weight, related to the weight of the structural reinforcer.
Claim 10
Dependent Claim
22 words
A catalyst as defined in claims 5 or 6, wherein the carrier material is present in the form of molded bulk material.
Claim 11
Dependent Claim
29 words
A catalyst as defined in claims 5 or 6, wherein a coating comprising the components (a)-(d) is present on structurally reinforcing bulk material bodies of ceramic or of metal.
Claim 12
Dependent Claim
96 words
A process for the production of the catalyst as defined in claim 1 comprising impregnating a carrier material of Al 2 O 3 of the transition series, optionally lattice stabilized with an alkaline earth metal, with an aqueous solution comprising cerium, zirconium and iron salts or mixing with a mixture of their respective oxides, tempering for 30-180 minutes in air at 500°-700° C., thereupon impregnating the carrier with an aqueous solution comprising a salt of platinum, and rhodium thereafter drying the carrier and subsequently treating at temperatures of 250°-650° C. in a gas stream containing hydrogen.
Claim 13
Dependent Claim
37 words
A process as defined in claim 10, wherein the carrier material is tempered prior to impregnation with cerium- , zirconium- and iron salts or prior to the addition of the oxides of these elements, at 900° C.
Claim 14
Dependent Claim
26 words
A process as defined in claim 11 wherein the carrier material is saturated prior to tempering with an aqueous solution of an alkaline earth metal salt.
Claim 15
Dependent Claim
77 words
A process as defined in claims 10, wherein cerium nitrate, cerium acetate, ammonium cerium nitrate, cerium carbonate, cerium oxalate, cerium chloride or cerium citrate are used as the cerium salt; zirconium carbonate, zirconium acetate, zirconium nitrate, ammonium zirconium carbonate, zirconium oxychloride, zirconium formiate or zirconium propionate are used as the zirconium salt and in that iron formiate, iron nitrate, iron oxalate, iron thiocyanate, iron (II)-acetate, iron acetyl acetonate or ammonium iron citrate are used as iron salts.
Claim 16
Dependent Claim
113 words
A process for the production of the catalyst as defined in claim 5 comprising impregnating a carrier material of Al 2 O 3 of the transition series, optionally lattice stabilized with an alkaline earth metal, with an aqueous solution comprising cerium, zirconium and iron salts or mixing with a mixture of their respective oxides, tempering for 30-180 minutes in the air at 500°-700° C., thereupon impregnating the carrier with an aqueous solution comprising a salt of platinum, rhodium and at least one of the base metal elements aluminum, titanium, tin, chromium, manganese, cobalt and nickel, thereafter drying the carrier and subsequently treating at temperatures of 250°-650° C. in a gas stream containing hydrogen.
Claim 17
Dependent Claim
35 words
A process as defined in claim 14 wherein aluminum or nickel is used as a base metal and platinum group metals and aluminum or nickel are used in a weight ratio of 3:1-1:1, or 4:1-2:1.
Claim 18
Dependent Claim
36 words
A process as defined in claim 14 wherein the carrier material is tempered prior to impregnation with cerium- , zirconium- and iron salt or prior to the addition of oxides of these elements at 900° C.
Claim 19
Dependent Claim
26 words
A process as defined in claim 16 wherein the carrier material is saturated prior to tempering with the aqueous solution of an alkaline earth metal salt.
Claim 20
Dependent Claim
77 words
A process as defined in claim 14 wherein cerium nitrate, cerium acetate, ammonium cerium nitrate, cerium carbonate, cerium oxalate, cerium chloride or cerium citrate are used as the cerium salt; zirconium carbonate, zirconium acetate, zirconium nitrate, ammonium zirconium carbonate, zirconium oxychloride, zirconium formiate or zirconium propionate are used as the zirconium salt and in that iron formiate, iron nitrate, iron oxalate, iron thiocyanate, iron (II)-acetate, iron acetyl acetonate or ammonium iron citrate are used as iron salts.
Claim 21
Dependent Claim
60 words
A process for as defined in claim 10, wherein the carrier material is first applied on the honeycomb shaped structural support of ceramic or metal or on the structurally reinforcing bulk material bodies by bringing these in contact with an aqueous dispersion of the carrier material in solution, after removal of excess dispersion, drying, calcining at temperatures of 900° C.
Claim 22
Dependent Claim
59 words
A process as defined in claim 14 wherein the carrier material is first applied on the honeycomb shaped structural support of ceramic or metal or on the structurally reinforcing bulk material bodies by bringing these in contact with an aqueous dispersion of the carrier material in solution, after removal of excess dispersion, drying, calcining at temperatures of 900° C.
Claim 23
Dependent Claim
55 words
A process as defined in claim 10 wherein the structural support is brought into contact with an aqueous dispersion of aluminum oxide of the transition series containing the salts of cerium, zirconium and iron in solution or the oxides of these elements, removing the excess dispersion, drying and calcinining at temperatures of 500° C.-700° C.
Claim 24
Dependent Claim
16 words
A process as in claim 21, wherein alkaline earth metal-stabilized Al 2 O 3 is used.
Claim 25
Dependent Claim
53 words
A process as defined in claim 14 wherein the structural support is brought into contact with an aqueous dispersion of aluminum oxide of the transition series containing the salts of cerium, zirconium and iron in solution or the oxides of these elements, removing the excess dispersion, drying, calcining at temperatures of 500°-700° C.
Claim 26
Dependent Claim
17 words
A process as defined in claim 23 wherein alkaline earth metal-stabilized Al 2 O 3 is used.
Claim 27
Dependent Claim
14 words
A catalyst as defined in claim 5, wherein said alkaline earth metal is calcium.
Claim 28
Dependent Claim
17 words
A process as defined in claim 12 wherein the alkaline earth metal salt is a calcium salt.
Claim 29
Dependent Claim
17 words
A process as defined in claim 17 wherein the alkaline earth metal salt is a calcium salt.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-12 | 1985-04-13 | 1985-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-12 | 1989-04-13 | 1989-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-12 | 1993-04-13 | 1993-10-13 | $7700.00 | Window Closed / Lapsed |