초록 ▼

Provided are an exhaust treatment catalyst and an exhaust article containing the catalyst. The catalyst comprises: (a) a carrier; (b) a first layer deposited on the carrier, said first layer comprising substantially only at least one refractive metal oxide; (c) a second layer deposited on the fir

Provided are an exhaust treatment catalyst and an exhaust article containing the catalyst. The catalyst comprises: (a) a carrier; (b) a first layer deposited on the carrier, said first layer comprising substantially only at least one refractive metal oxide; (c) a second layer deposited on the first layer, said second layer comprising substantially only at least one oxygen storage component and at least one binder therefor; and (d) a third layer deposited on the second layer, said third layer comprising at least one layer of one or more platinum group metal components supported on a refractory metal oxide support. Optionally, a fourth layer is deposited on the third layer wherein the fourth layer comprises one or more platinum group metal components supported on a refractory metal oxide support. As a further option, an overcoat layer may be deposited on the third or fourth layer wherein the overcoat layer comprises a catalyst poison sorbent. Also provided are methods for preparing the catalyst and methods for monitoring the exhaust storage capacity of an exhaust article containing the catalyst.

대표청구항 ▼

What is claimed is: 1. An exhaust gas treatment catalyst comprising: (a) a carrier; (b) a first washcoat layer deposited on the carrier, said first washcoat layer comprising substantially only at least one refractory metal oxide; (c) a second washcoat layer deposited on the first washcoat layer, sa

What is claimed is: 1. An exhaust gas treatment catalyst comprising: (a) a carrier; (b) a first washcoat layer deposited on the carrier, said first washcoat layer comprising substantially only at least one refractory metal oxide; (c) a second washcoat layer deposited on the first washcoat layer, said second washcoat layer comprising substantially only at least one oxygen storage component and at least one binder therefor; and (d) a third washcoat layer deposited on the second washcoat layer, said third washcoat layer comprising at least one layer of one or more platinum group metal components supported on a refractory metal oxide support. 2. The catalyst of claim 1 wherein the third washcoat layer further comprises at least one oxygen storage component and at least one binder therefor. 3. The catalyst of claim 1 further comprising a fourth washcoat layer deposited on the third washcoat layer, said fourth washcoat layer comprising one or more platinum group metal components supported on a refractory metal oxide support. 4. The catalyst of claim 3 wherein the fourth washcoat layer further comprises at least one oxygen storage component and at least one binder therefor. 5. The catalyst of claim 3 wherein the refractory metal oxide employed in the first layer, third layer and the fourth layer is independently selected from the group consisting of alumina; titania; zirconia; mixtures of alumina with one or more of titania, zirconia, and ceria; ceria coated on alumina; and titania coated on alumina. 6. The catalyst of claim 3 further comprising an overcoat layer deposited on the third or the fourth washcoat layer, said overcoat layer comprising at least one catalyst poisons sorbent. 7. The catalyst of claim 6 wherein the carrier comprises a ceramic or metal having a honeycomb cellular structure comprising hexagonal, rectangular or square cells. 8. The catalyst of claim 7 wherein the first, second, third, fourth and overcoat layers have thicknesses at their respective edges and corners of the cells as follows: Layer Edge Thickness, μ Corner Thickness, μ First about 3 to about 15 about 30 to about 200 Second about 5 to about 15 about 30 to about 100 Third about 5 to about 15 about 30 to about 100 Fourth about 5 to about 15 about 30 to about 100 Overcoat about 5 to about 15 about 30 to about 100. 9. An exhaust gas treatment system comprising the catalyst of claim 7, an upstream EGO or air/fuel ratio sensor, and a downstream EGO sensor. 10. An exhaust gas treatment system comprising the catalyst of claim 3, an upstream EGO or air/fuel ratio sensor, and a downstream EGO sensor. 11. The catalyst of claim 1 wherein the oxygen storage component is selected from the group consisting of ceria, praseodymia, a ceria-praseodymia composite, a ceria-praseodymia-zirconia composite and a ceria-praseodymia-zirconia-neodymia composite, and the binder comprises zirconia. 12. The catalyst of claim 1 wherein the catalyst comprises at least two catalytic zones. 13. The catalyst of claim 1, wherein the first layer comprises at least 76 weight % of one refractory metal oxide. 14. The catalyst of claim 13, wherein the first layer comprises active ingredients in a quantity not exceeding approximately 12 weight %. 15. The catalyst of claim 14, wherein the first layer comprises stabilizers in a quantity not exceeding approximately 12 weight %. 16. The catalyst of claim 15, wherein the second layer comprises at least 76 weight % of one refractory metal oxide. 17. The catalyst of claim 16, wherein the second layer comprises active ingredients in a quantity not exceeding approximately 12 weight %. 18. The catalyst of claim 17, wherein the second layer comprises stabilizers in a quantity not exceeding approximately 12 weight %. 19. An exhaust gas treatment system comprising the catalyst of claim 1, an upstream EGO or air/fuel ratio sensor, and a downstream EGO sensor.