Exhaust gas purifying catalyst
AssigneesICT Co., Ltd., International Catalyst Technology, Inc.
InventorsShigeyoshi Taniguchi, Makoto Horiuchi
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Abstract
An exhaust gas purifying catalyst having a refractory three-dimensional structure coated with a catalytically active component comprising at least one kind of noble metals, a refractory inorganic oxide, and a zirconium oxide containing cerium and lanthanum, the crystal structure of the zirconium oxide containing cerium and lanthanum being a tetragonal structure of zirconium oxide.
Claims16
An exhaust gas purifying catalyst comprising:
- a catalytically active component comprising at least one kind of noble metals, a refractory inorganic oxide, and a zirconium oxide containing cerium and lanthanum;
- and
- a refractory three-dimensional structure coated with the catalytically active component;
- wherein said zirconium oxide containing cerium and lanthanum has a tetragonal crystal structure of zirconium oxide, a weight ratio of cerium as CeO2 to zirconium as ZrO2 in the range of 1:8 to 1:1, and a weight ratio of lanthanum as La2O3 to zirconium as ZrO2 in the range of 1:1.5 to 1:60.
A catalyst according to claim l, wherein the weight ratio of lanthanum as La2O3 to zirconium as ZrO2 is in the range of 1:1.5 to 1:40.
A method for simultaneous purification of carbon monoxide, hydrocarbon, and nitrogen oxide contained in the exhaust gas emitted from an internal combustion engine by the use of an exhaust gas purifying catalyst comprising:
- a catalytically active component comprising at least one kind of noble metals, a refractory inorganic oxide, and a zirconium oxide containing cerium and lanthanum;
- and a refractory three-dimensional structure coated with the catalytically active component;
- wherein said zirconium oxide containing cerium and lanthanum has a crystal structure of a tetragonal structure of zirconium oxide, a weight ratio of cerium as CeO2 to zirconium as ZrO2 in the range of 1:8 to 1:1, and a weight ratio of lanthanum as La2O3 to zirconium ZrO2 in the range of 1:1.5 to 1:60.
Dependencies are inferred from the claim text.