Inorganic mixed oxide and catalyst for purification of exhaust gas using the same

A particulate inorganic mixed oxide comprising:

• aluminum;
• zirconium;
• cerium;
• lanthanum;
• and
• an additional element selected from the group consisting of neodymium and praseodymium, 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 lanthanum and the additional element 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 additional element is locally increased in a surface layer portion thereof, and
• an amount of the 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.