The catalytic oxidation of NO is investigated over metal oxide catalysts supported on γ alumina. The experiment results show that P type metal oxide catalysts display relatively high catalytic acti vity and the sequence of activities for NO oxidation is as follows: Mn>Cr>Co>Cu>Fe>Ni>Zn By using a micro reactor, the reaction mechanism of catalytic oxidation over a typical P type metal oxide catalyst MnO 2 can be expressed as: 12O 2+v k 6 k′ 6O(ads) O(ads)+NO(g) k 7 k′ ...