CERIA-ZIRCONIA-BASED COMPOSITE OXIDE AND METHOD FOR PRODUCING SAME, AND EXHAUST GAS PURIFICATION CATALYST INCLUDING CERIA-ZIRCONIA-BASED COMPOSITE OXIDE

摘要

A ceria-zirconia-based composite oxide containing a composite oxide of ceria and zirconia is provided, in which primary particles having a particle diameter of 1.5 to 4.5 μι&eegr; account for, on a particle number basis, at least 50% of all primary particles in the ceria-zirconia-based composite oxide, and the molar ratio of cerium to zirconium ([cerium]: [zirconium]) in the ceria-zirconia-based composite oxide is between 43 :57 and 55:45.