The effect of the decreased defect concentration in ceria by the thermal treatment prior to the Pt loading on the Pt-ceria interaction and the CO oxidation ability of Pt / CeO 2 catalysts

The CO oxidation ability can be modulated by controlling the metal-support interaction of Pt/CeO2 catalysts. Pt/(800C)CeO2 prepared by the thermal treatment of ceria at 800 C before loading Pt maintained the much higher Pt dispersion than Pt/γ-Al2O3 after the thermal aging at 800 C. In addition, the light-off curve of the CO oxidation shifted to the lower temperature by more than 70 C in Pt/(800C)CeO2 than in Pt/CeO2 catalyst without the thermal treatment. Such enhanced activity is explained by the formation of PtO2 species that interact weakly with ceria rather than Pt-O-Ce species interacting strongly with ceria.