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/CeO 2 catalysts. The Pt/(800C)CeO 2 sample prepared by the thermal treatment of ceria at 800 °C before loading Pt maintained the much higher Pt dispersion than Pt/γ-Al 2 O 3 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)CeO 2 catalyst was order of magnitude higher than that of the Pt/CeO 2 catalyst. Such enhanced activity is explained by the weakened Pt–ceria interaction in Pt/(800C)CeO 2, which is evidenced by the formation of PtO 2 species that interact weakly with ceria rather than that of Pt–O–Ce species interacting strongly with ceria. The presence of PtO 2 species appears to be essential for the high CO oxidation ability.