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US 11,110,396 B2Granted
Catalyst for purification of exhaust gas from internal combustion engine and exhaust gas purifying method using the catalyst
AssigneeUmicore Shokubai Japan Co., Ltd.
InventorsShigekazu Minami, Masanori Ikeda, Yuta Akasaka, Hirotaka Kuno, Hideki Goto
Life of this patent
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Abstract
An object is to provide a means for suppressing a deterioration in catalytic performance even after being exposed to high temperature exhaust gas containing a phosphorus compound for a long period of time. An exhaust gas purifying catalyst including palladium supported on cerium-aluminum composite oxide containing cerium at from 3 to 60% by mass in terms of cerium oxide.
Claims7
An exhaust gas purifying catalyst having two or more catalyst layers on a three-dimensional structure, wherein the two or more catalyst layers comprise
- a lower layer comprising a palladium-supporting cerium-aluminum composite oxide, wherein palladium is supported on a cerium-aluminum composite oxide containing cerium at from 3 to 60% by mass in terms of cerium oxide, and
- an upper layer comprising a rhodium-supporting inorganic oxide, wherein rhodium is supported on the inorganic oxide, and the inorganic oxide is not a combination of cerium and aluminum,
- cerium in the cerium-aluminum composite oxide is uniformly dispersed in the cerium-aluminum composite oxide,
- a part of palladium supported is aluminum-cerium-palladium composite in X-ray diffraction measurement by CuKα ray after the exhaust gas purifying catalyst is exposed to a high temperature of 1000° C. or higher, and
- the aluminum-cerium-palladium composite is AlxCeyPdz, wherein x=9 to 1, y=5 to 1, and z=7 to 1.
2 more elements
Dependencies are inferred from the claim text.