▎ 摘　　要

40% (w) Pt/graphene composites were prepared by sodium borohydride chemical co-reduction, and were subsequently used as an electrocatalyst for oxygen reduction reactions. The electrocatalytic activity and stability was evaluated by cyclic voltammetry. The results indicated that the initial activity of Pt/graphene was lower than that of Pt/C due to the oxygen diffusion inhibition; however, the Pt/graphene showed superior durability characteristics. Degradation tests showed a 50% degradation of Pt/graphene, which was substantially less than that of Pt/C (79%). X-ray diffraction and transmission electron microscope results showed that the composite formed strong interactions between the platinum nanoparticles and the graphene supports. The graphene supports may also prevent the graphene sheets from folding or re-stacking, which would hinder platinum nanoparticles' aggregation. The performance of a single cell was also tested, confirming an improvement in durability.