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US 2001/0022956 A1Published application
Catalyst for purifying exhaust gas and method for purifying exhaust gas with the catalyst
AssigneeMazda Motor Corporation
InventorsKenji Okamoto, Akihide Takami, Hiroshi Yamada, Seiji Miyoshi
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Abstract
The present invention provides a catalyst for purifying an exhaust gas having excellent heat resistance and a small level of deterioration of the purifying ability of the exhaust gas even if the catalyst is exposed to a high temperature atmosphere for a long time. The catalyst for purifying an exhaust gas comprises a catalytic metal for oxidizing HC and CO and reducing NOx for purification, and a mixed oxide containing Ce, Zr and Sr.
Claims7
A catalyst for purifying an exhaust gas comprising:
- a catalytic metal that serves for oxidization of HC and CO in the exhaust gas containing oxygen and reduction of NOx in said gas, and a mixed oxide comprising Ce, Zr and Sr.
A catalyst for purifying an exhaust gas, comprising:
- a carrier,
- an inner catalytic layer disposed on the carrier, comprising:
- a precious metal, a NOx storage material that absorbs NOx in the exhaust gas in an oxygen-excessive atmosphere in which an oxygen concentration in the exhaust gas is high, and releases the absorbed NOx by reduction of the oxygen concentration, and
- a mixed oxide containing Ce, Zr, and Sr, and an outer catalytic layer disposed on the inner catalytic layer, comprising:
- a precious metal, and
- zeolite.
3 more elements
Dependencies are inferred from the claim text.