OXIDATION CATALYST COMPOSITION AND PM OXIDATION CATALYST

摘要

[PROBLEMS] To provide an oxidation catalyst composition having excellent low-temperature activity and a PM oxidation catalyst with which particulate and other matters discharged from an internal combustion engine can be oxidized or burned even at a relatively low temperature. [MEANS FOR SOLVING PROBLEMS] The oxidation catalyst composition comprises cerium, manganese, and a metal (M) (M is a trivalent metal element excluding cerium). When the composition is analyzed by XPS and the orbital energies are subjected to peak separation using the Gaussian function, the Ce<SUP>4+</SUP>/Ce<SUP>3+</SUP> atomic amount ratio (at.% ratio) is 1.7 or higher and the amount of Mn<SUP>2+</SUP> is 5 at.% or larger, at least part of the manganese having been combined. The metal (M) may be ytterbium, thulium, erbium, holmium, dysprosium, gadolinium, europium, samarium, promethium, neodymium, praseodymium, scandium, yttrium, aluminum, gallium, etc.