INORGANIC MIXED OXIDE AND EXHAUST GAS PURIFICATION CATALYSTS MADE BY USING THE SAME

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A particulate inorganic mixed oxide comprising : aluminum; zirconium; cerium; and first and second additional elements each selected from the group consisting of rare earth elements other than cerium and alkaline earth elements, wherein a content of aluminum in the inorganic mixed oxide is 60 to 90 at%, in terms of element content, relative to a total amount of elements which form cations in the inorganic mixed oxide; a content of cerium in the inorganic mixed oxide is 0.4 to 50 at%, in terms of element content, relative to a total amount of zirconium and cerium in the inorganic mixed oxide; a content of a total amount of the first and second additional elements is 1 to 12 at%, in terms of element content, relative to the total amount of the elements which form cations in the inorganic mixed oxide; at least 80% of primary particles of the inorganic mixed oxide have a particle diameter of 100 nm or less; at least a part of the primary particles have an enriched surface region where a content of the second additional element is locally increased in a surface layer portion thereof; and an amount of the second additional element in the enriched surface region is 0.1 to 0.95% by mass, in terms of oxide, relative to a whole amount of the inorganic mixed oxide.