Abstract
Gold-based catalysts supported on Co 3O 4, on CeO 2 and on mixed Co 3O 4–CeO 2 oxides were prepared by co-precipitation. They were tested in the catalytic oxidation of CO and CH 4, in separate tests, and their activities were compared with that of the bare oxides. Tests of CH 4 oxidation were performed in two consecutive runs in order to evaluate the catalysts stability. The effect of SO 2 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 CeO 2 was the most active in CO oxidation whereas Au supported on Co 3O 4 was the most active for methane total oxidation. Synergy between the two oxides was not observed for gold on mixed Co 3O 4–CeO 2 system. However, in consecutive runs of methane oxidation and in the presence of SO 2, Au supported on mixed Co 3O 4–CeO 2 exhibited higher stability and superior SO 2 tolerance as compared to the single oxide catalysts.
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