In situ DRIFTS investigation of low temperature CO oxidation over manganese oxides supported Pd catalysts

Abstract A series of different manganese oxides supported Pd catalysts with low Pd loading of 0.3 wt.% have been synthesized and applied to CO catalytic oxidation at low-temperature. In situ DRIFTS was employed to dynamically trace CO oxidation process. It was found that the CO catalytic activity decreased in the order of Pd/OMS-2 > Pd/MnO2 > Pd/Mn2O3 >> Pd/Mn3O4. More interestingly, the Pd/OMS-2 catalyst exhibited exceptionally high activity of T99 = 16 °C, as well as higher reducibility. Furthermore, XPS and in situ DRIFTS results indicated that a substantial of lattice oxygen participated in CO oxidation, contributing to the optimal activity over Pd/OMS-2. While the low reactivity over Pd/Mn3O4 was ascribed to a small amount of lattice oxygen and the strongly adsorbed CO on Pd0.