US5021389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-way catalyst for automotive emission control and method of making the catalyst
Assignee: University of Michigan (System)
•
Filing: 1989-11-22
•
Granted: 1991-06-04
•
Expires: 2009-11-22
Abstract
Abstract A three-way catalyst for automotive emission control having a mechanical carrier having a support comprised substantially of alumina, a lanthanum oxide coating decorated onto the support, a catalytic compound discontinuously supported on the decorated support having a major constituent of palladium, and a discontinuous phase of titanium oxide on the alumina, lanthana, and catalytic compound composite. The method of making such three-way catalyst for automotive emission control, comprises coating an alumina support with lanthana, impregnating the coated support with a palladium compound to form a discontinuous phase on the lanthana, and impregnating the coated support and catalytic compound with an organo-titania compound to form a discontinuous phase on the lanthana and palladium compound.
Inventors
- 👤 Mohinder S. Chattha
- 👤 William L. H. Watkins
- 👤 Haren S. Gandhi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:56
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; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
73 words
A three-way catalyst for automotive emission control, comprising: (a) a mechanical carrier having a support comprised substantially of alumina; (b) discontinuous lanthanum oxide on said support; (c) a catalytic palladium compound supported discontinuously on the decorated support having a major constituent of palladium; and (d) a discontinuous phase of titanium oxide on said alumina, lanthana, and catalytic compound composite, said titanium oxide being 0.1-8.0% by weight of the total weight of the catalyst.
Claim 2
Dependent Claim
73 words
A three-way catalyst for automotive emission control, comprising: (a) a mechanical carrier having a support comprised substantially of alumina; (b) discontinuous lanthanum oxide on said support; (c) a catalytic palladium compound supported discontinuously on the decorated support having a major constituent of palladium; and (d) a discontinuous phase of titanium oxide on said alumina, lanthana, and catalytic compound composite, said titanium oxide being 0.1-8.0% by weight of the total weight of the catalyst.
Claim 3
Dependent Claim
19 words
The catalyst as in claim 1, in which said discontinuous palladium compound covers 0.05-10% of said lanthana decorated support.
Claim 4
Dependent Claim
49 words
The catalyst as in claim 1, characterized by a conversion efficiency of HC at 350° C. of at least 60 and at 400° C. of at least 84, and a conversion efficiency of NO at 150° C. of at least 80 and at 500° C. of at least 92.
Claim 5
Dependent Claim
27 words
The catalyst as in claim 1, in which said discontinuous titania phase is a washcoat constituting 0.1% up to 8% of the total weight of the catalyst.
Claim 6
Dependent Claim
21 words
The catalyst as in claim 4, in which said catalytic palladium compound forms 0.05-5% of the total weight of the catalyst.
Claim 7
Dependent Claim
21 words
The catalyst as in claim 1, in which said discontinuous titania phase is 0.1-2.0% of the total weight of the catalyst.
Claim 8
Dependent Claim
16 words
The catalyst as in claim 1, in which said catalytic compound contains up to 2.5% platinum.
Claim 9
Dependent Claim
33 words
The catalyst as in claim 1, in which no greater than 40% of the surface area of each exposed particle of catalytic compound or decorated support is covered by said titanium oxide phase.
Claim 10
Independent Claim
87 words
A method of making a three-way catalyst for automotive emission control, comprising: (a) discontinuously coating an alumina support with lanthana; (b) impregnating the coated support with a palladium compound to form a discontinuous phase on the lanthana and support; and (c) impregnating the coated support and catalytic compound with an organo-titanium compound to form, upon heating, a discontinuous titanium oxide phase on the exposed portions of said discontinuous lanthana and palladium compound phases, said compound being present in an amount of 0.1-8% by weight of the catalyst.
Claim 11
Independent Claim
87 words
A method of making a three-way catalyst for automotive emission control, comprising: (a) discontinuously coating an alumina support with lanthana; (b) impregnating the coated support with a palladium compound to form a discontinuous phase on the lanthana and support; and (c) impregnating the coated support and catalytic compound with an organo-titanium compound to form, upon heating, a discontinuous titanium oxide phase on the exposed portions of said discontinuous lanthana and palladium compound phases, said compound being present in an amount of 0.1-8% by weight of the catalyst.
Claim 12
Dependent Claim
50 words
The method as in claim 9, in which palladium is added in a diluted palladium nitrate solution with the amount of acid being regulated to a pH of 3-5, and after drying the support wetted with said acid, calcining the composite at a temperature in the range of 450°-650° C.
Claim 13
Dependent Claim
34 words
The method as in claim 9, in which said organo-titanium compound is dissolved in a liquid for wetting said composite, said wetted composite being calcined at a temperature of 400°-600° C. for 4-12 hours.
Claim 14
Dependent Claim
32 words
The method as in claim 11, in which said calcination is staged to include heating to 250°-280° C. for 1-1/2 to 2-1/2 hours, and thence heating to 400°-600° C. for 5-10 hours.
Claim 15
Dependent Claim
53 words
The method as in claim 9, in which said support is a collection of aggregates prepared by (i) wetting a particulate source of alumina with dilute nitric acid to form a slurry, (ii) drying said slurry to form a cake, and (iii) crushing said cake to an average particle size of 25-40 mesh.
Claim 16
Dependent Claim
14 words
The method as in claim 9, in which said organo-titanium compound is titanium butoxide.
References Cited (Backward Citations)
US4123391A
Cited
US4283308A
Cited
US4350613A
Cited
US4504598A
Cited
US4624941A
Cited
US4650782A
Cited
US4868148A
Cited
US4791091A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-03 | 1994-12-03 | 1995-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-03 | 1998-12-03 | 1999-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-03 | 2002-12-03 | 2003-06-04 | $7700.00 | Window Closed / Lapsed |