Catalyst for purifying exhaust gas and method

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PROBLEM TO BE SOLVED : To provide a catalyst for purifying exhaust gas, in which a noble metal particle is restrained from being agglomerated even when the catalyst is exposed to high-temperature exhaust gas for a long time, in the grain-grown one of which a noble metal is dispersed again in a short time in a low temperature range to regenerate the grain-grown catalyst and which can be regenerated in such a state that the catalyst is mounted in an exhaust gas system of an internal-combustion engine and to provide a method for regenerating the catalyst. SOLUTION : The catalyst for purifying exhaust gas is provided with : a carrier containing a multiple oxide of zirconia and/or alumina and at least one element selected from the group consisting of alkaline-earth metal elements, rare earth elements and group 3A elements; a noble metal deposited on the carrier; and an additional component which is deposited on the carrier and contains at least one element selected from the group consisting of alkaline-earth metal elements, rare earth elements and group 3A elements. The catalyst for controlling exhaust gas is characterized in that the amount of the noble metal to be deposited is within 0.05-2 mass% of the catalyst and the molar ratio of (the amount of the additional component to be deposited)/(the amount of the noble metal to be deposited) in terms of metals is within 0.5-20. COPYRIGHT : (C)2008, JPO&INPIT