▎ 摘　　要

Oxygen storage capacity is influenced by the morphology and crystal-plane(s) of CeO2, which can thus affect the ability of this material to oxidise carbon monoxide. To investigate the effect of different morphologies/crystal-planes of CeO2 on the electrocatalytic performance of DMFCs (Direct Methanol Fuel Cell), three different types of CeO2 nanocrystals with different crystal-planes were synthesised and later assembled into Pt-xCeO(2)/Graphene composites with graphene and Pt nanoparticles as the electrocatalyst for DMFCs. According to the HRTEM images, the original morphology and crystal-plane structures of CeO2 are essentially maintained in the three types of Pt-xCeO(2)/Graphene composite catalysts investigated in this work. The catalytic performance of the Pt-xCeO(2)/Graphene composites for methanol electrocatalytic oxidation was investigated by a series of electrochemical measurements. Compared with the other catalysts, Pt-rCeO(2)/Graphene demonstrates superior catalytic activity (onset potential: 0.15 V) and the strongest resistance to poisoning by carbonaceous species (I-f/I-b: 2.11). The results of H-2-TPR shows that rCeO(2) with the {110} facet has the best surface reducibility among the xCeO(2) with different facets being investigated, which provides a rationale for the superior performance of the Pt-rCeO(2)/Graphene catalyst. This study indicates that metallic oxides with a suitable crystal plane and shape can effectively enhance the electrocatalytic performance of Pt-based catalysts for methanol electrooxidation.