摘要 |
A composite oxide for exhaust gas purification catalysts, which comprises Ce, Bi, R and oxygen and satisfies 0 < x ‰¤ 0.4 and 0 < y < 1.0 when the molar ratio of Ce, Bi and R of the oxide is represented as (1-x-y), x and Y respectively. The composite oxide has an X-ray diffraction peak corresponding to that of a fluorite structure. In the composite oxide, R contains one or two of Pr and Tb. The exhaust gas purification catalyst is favorable for a PM combustion catalyst. |