The mol ratio of Ce and Bi and the PR in bulk composition in

摘要

PROBLEM TO BE SOLVED: To provide a composite oxide for an exhaust gas cleaning catalyst, which is not easily poisoned by sulfur oxide components included in an exhaust gas and is capable of suppressing the decline of catalyst activity, and an exhaust gas cleaning filter using it.;SOLUTION: In the composite oxide for the exhaust gas cleaning catalyst constituted of Ce, Bi, Pr and oxygen, when the mole ratio of Ce, Bi and Pr in a bulk composition is defined as Ce:Bi:Pr=(1-x-y):x:y, 0x≤0.3 and 0y≤0.5 are satisfied. When the mole ratio of Ce, Bi and Pr in a surface composition is defined as Ce:Bi:Pr=(1-p-q):p:q, 0p≤0.5 and 0q≤0.5 (except for the case that p and q are both 0.5) are satisfied.;COPYRIGHT: (C)2010,JPO&INPIT