Catalyst for purifying exhaust gas and method

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PROBLEM TO BE SOLVED : To provide an exhaust gas-purifying catalyst capable of sufficiently suppressing a coagulation of noble metal particles even if they are exposed to a high-temperature exhaust gas for a long period of time to sufficiently suppress a grain growth of a noble metal for a long period of time, thereby enabling the system to sufficiently suppress the deterioration of a catalytic activity, easily regenerating the catalytic activity by re-dispersing the noble metal that is grain grown when in use, and easily regenerating the catalyst even if the catalyst is mounted on an exhaust system of an internal engine, and to provide a method for regenerating the exhaust gas-purifying catalyst. SOLUTION : The exhaust gas-purifying catalyst having a carrier containing a composite oxide with at least one element selected from a group consisting of zirconia and/or alumina, alkali earth metal element, rare earth element and IIIA group element, a noble metal that is supported in the carrier, and iron that is supported in the carrier, wherein a supported amount of the noble metal should be in a scope of 0.05 to 2 mass% to the mass of the catalyst, and a supported amount of iron should be in a scope of 0.8 to 12 that is mole ratio (amount of iron/amount of noble metal) to the mass of the noble metal in metal conversion. COPYRIGHT : (C)2008, JPO&INPIT