“…Third, the catalysts with the maximum amount of Pd and lowest calcination temperature of CoMn oxides exhibited the highest activity and also displayed good activity for the catalytic combustion of benzene (1500 ppm, 20,000 h À1 ); complete conversion was achieved at 300 8C. The results demonstrated that increasing amounts of noble metal improved the activity of CO oxidation, which was consistent with reports by Requies's [11]. After promoting activity with an increasing amount Pd, both the reduction and oxidation of the cobalt phase were greatly enhanced due to hydrogen or oxygen spill-over because palladium was intrinsically effective for molecular hydrogen and oxygen dissociation.…”