Claims
- 1. A multi-component catalyst for removing carbon monoxide, hydrocarbons, and nitrogen oxides contained in exhaust gases from a lean-burn internal combustion engine, said engine operating with an air-fuel ratio above about 18, comprising:
- (a) a first catalytic component comprising a catalyst selected from the group consisting of:
- (i) alumina having dispersed thereon a catalytically effective amount of a material selected from the group consisting of Pt/Au alloys and mixtures, oxidized Cu, oxidized Ag, Ga.sub.2 O.sub.3, In.sub.2 O.sub.3, and dispersed SnO.sub.2 ;
- (ii) zeolite having dispersed thereon a catalytically effective amount of Cu and Ag; and,
- (iii) .gamma.-alumina having dispersed thereon a catalytically effective amount of CoO;
- (b) a second catalytic component comprising a catalyst selected from the group consisting of alumina having dispersed thereon a catalytically effective amount of Pt/Ag alloys and/or mixtures and molecular sieves having dispersed thereon a catalytically effective amount of Rh; and
- (c) a third catalytic component comprising a catalytically effective amount of Pt dispersed on a support selected from the group consisting of .alpha.-alumina and Y-zeolite.
- 2. A multi-component catalyst for removing carbon monoxide, hydrocarbons, and nitrogen oxides contained in exhaust gases from a lean-burn internal combustion engine, said engine operating with an air-fuel ratio above about 18, comprising:
- a first catalytic component comprising a catalytically effective amount of Pt dispersed on a mixture of alumina and aluminosilicate, said aluminosilicate being in the proton form, possessing the MFI structure and having a Si/Al mole ratio of 19; and
- a second catalytic component comprising a catalytically effective amount of Pt dispersed on dealuminated Y-zeolite crystals, said crystals being in the proton form and having diameters within a range of 0.5 .mu.m. to 50 .mu.m., wherein the Pt is dispersed on the crystals in a manner such that at least 90% of the Pt is located within 500 .ANG. of the exterior surface of the crystals.
- 3. A multi-component catalyst for removing carbon monoxide, hydrocarbons, and nitrogen oxides contained in exhaust gases from a lean-burn internal combustion engine, said engine operating with an air-fuel ratio above about 18, comprising:
- a first catalytic component comprising a catalyst selected from the group consisting of:
- (i) alumina having dispersed thereon a catalytically effective amount of a material selected from the group consisting of Pt/Au alloys and mixtures, oxidized Cu, oxidized Ag, Ga.sub.2 O.sub.3, In.sub.2 O.sub.3, and dispersed SnO.sub.2 ; and,
- (ii) zeolite having dispersed thereon a catalytically effective amount of Cu and Ag; and
- a second catalytic component comprising a catalyst selected from the group consisting of:
- (i) a catalytically effective amount of Pt dispersed on alumina and an aluminosilicate, said aluminosilicate being in the proton form, possessing the MFI structure and having a Si/Al mole ratio of 19; and
- (ii) a catalytically effective amount of Pt dispersed on dealuminated Y-zeolite crystals, said crystals being in the proton form and having diameters within a range of 0.5 .mu.m. to 50 .mu.m., wherein the Pt is dispersed on the crystals in a manner such that at least 90% of the Pt is located within 500 .ANG. of the exterior surface of the crystals.
- 4. A multi-component catalyst for removing carbon monoxide, hydrocarbons, and nitrogen oxides contained in exhaust gases from a lean-burn internal combustion engine, said engine operating with an air-fuel ratio above about 18, comprising:
- a first catalytic component comprising a catalytically effective amount of Pt dispersed on
- a mixture of alumina and aluminosilicate, said aluminosilicate being in the proton form, possessing the MFI structure and having a Si/Al mole ratio of 19; and
- a second catalytic component comprising a catalytically effective amount of Pt dispersed on dealuminated Y-zeolite crystals, said crystals being in the proton form and having diameters within a range of 0.5 .mu.m. to 50 .mu.m., wherein the Pt is dispersed on the crystals in a manner such that at least 90% of the Pt is located within 500 .ANG. of the exterior surface of the crystals.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 07/990,216, filed Dec. 14, 1992, now U.S. Pat. No. 5,894,068.
US Referenced Citations (3)
Foreign Referenced Citations (2)
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6-142512A |
May 1994 |
JPX |
1384248 |
Feb 1975 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Kung et al. "Selective Reduction of NO.sub.x by Propene Over Au/.gamma.-Al.sub.2 O.sub.3 Catalysts" 11th International Congress on Catalysis--40th Anniversary Studies in Surface Science and Catalysis, vol. 101, Elsevier Science B. V. J. W. Hightower et al. (Editors), pp. 701-710, Jun. 30-Jul. 5, 1996. |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
990216 |
Dec 1992 |
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