Exhaust gas purifying catalyst
OwnerYuki Koda, Hirosuke Sumida +1inventors
InventorsYUKI KODA, HIROSUKE SUMIDA, MAKOTO KYOGOKU
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Abstract
An exhaust gas purifying catalyst includes at least an under catalytic layer disposed on a substrate containing a NOx absorbent which absorbs NOx in exhaust gas under existence of oxygen, releases absorbed NOx when an oxygen concentration of exhaust gas lowers and is restrained from absorbing NOx by sulfur compounds in exhaust gas and an outer oxide layer disposed over the under catalytic layer and containing a Ce—Zr composite oxide.
Claims10
An exhaust gas purifying catalyst comprising:
- a substrate;
- a catalytic layer containing a NOx absorbent which absorbs NOx in exhaust gas under existence of oxygen, releases said NOx when an oxygen concentration of said exhaust gas lowers and is restrained from absorbing NOx by sulfur compounds in said exhaust gas;
- and
- an oxide layer containing a Ce—Zr composite oxide;
- wherein said catalytic layer is disposed as an under layer on said substrate and said oxide layer is disposed as an outer layer over said oxide layer.
An exhaust gas purifying catalyst having a NOx reducing catalyst for deoxidization and reducing NOx in exhaust gas, a NOx absorbent for absorbing NOx in an exhaust gas under existence of oxygen and releasing said NOx when an oxygen concentration of said exhaust gas lowers, said NOx absorbent being restrained from absorbing NOx by sulfur compounds in said exhaust gas, and an auxiliary catalyst for promoting oxygen adsorption which absorbs oxygen in said exhaust gas and releases said oxygen when said oxygen concentration lowers, said exhaust gas purifying catalyst comprising:
- a substrate;
- a catalytic layer containing said NOx reducing catalyst, said NOx absorbent, and said auxiliary catalyst;
- and
- an oxide layer containing a Ce—Zr composite oxide which is higher in acidity than said auxiliary catalyst;
- wherein said catalytic layer is disposed as an under layer on said substrate and said oxide layer is disposed as an outer layer over said catalytic layer.
Dependencies are inferred from the claim text.