Effects of Ce on catalytic combustion of methane over Pd-Pt/Al ₂O ₃ catalyst

Activity and stability of 1%Pd-0.2%Pt/Al ₂O ₃ and 1%Pd-0.2%Pt/0.6%Ce/Al ₂O ₃ catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al ₂O ₃ catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al ₂O ₃ catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.