Support effect on the catalytic performance of Au/Co3O4–CeO2 catalysts for CO and CH4 oxidation

Gold-based catalysts supported on Co3O4, on CeO2 and on mixed Co3O4–CeO2 oxides were prepared by co-precipitation. They were tested in the catalytic oxidation of CO and CH4, in separate tests, and their activities were compared with that of the bare oxides. Tests of CH4 oxidation were performed in two consecutive runs in order to evaluate the catalysts stability. The effect of SO2 in the reactant mixture was investigated. The fresh and spent catalysts were analsed by XRD, BET, TPR and XPS techniques. Among the fresh catalysts, Au supported on CeO2 was the most active in CO oxidation whereas Au supported on Co3O4 was the most active for methane total oxidation. Synergy between the two oxides was not observed for gold on mixed Co3O4–CeO2 system. However, in consecutive runs of methane oxidation and in the presence of SO2, Au supported on mixed Co3O4–CeO2 exhibited higher stability and superior SO2 tolerance as compared to the single oxide catalysts.