Influence of the Defect Concentration of Ceria on the Pt Dispersion and the CO Oxidation Activity of Pt/CeO2

The CO oxidation ability can be modulated by controlling the metal–support interaction of Pt/CeO2 catalysts. The Pt/(800C)CeO2 sample 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, indicating its excellent thermal resistance against Pt sintering. In addition, the CO oxidation rate of the Pt/(800C)CeO2 catalyst was order of magnitude higher than that of the Pt/CeO2 catalyst. Such enhanced activity is explained by the weakened Pt–ceria interaction in Pt/(800C)CeO2, which is evidenced by the formation of PtO2 species that interact weakly with ceria rather than that of Pt–O–Ce species interacting strongly with ceria. The presence of PtO2 species appears to be essential for the high CO oxidation ability.