▎ 摘　　要

Combinations of graphene (Gr) and carbon black (C) were employed as binary carbon supports to fabricate Pd-based electrocatalysts via one-pot co-reduction with Pd2+. The electrocatalytic performance of the resulting Pd/Gr-C catalysts during the electrooxidation of formic acid was assessed. A Pd/Gr(0.3)C(0.7) (Gr oxide:C = 3:7, based on the precursor mass ratio) electrocatalyst exhibited better catalytic performance than both Pd/C and Pd/Gr catalysts. The current density generated by the Pd/Gr(0.3)C(0.7) catalyst was as high as 102.14 mA mgpd(-1), a value that is approximately 3 times that obtained from the Pd/C (34.40 mA mgpd(-1)) and 2.6 times that of the Pd/Gr material (38.50 mA mg(pd)(-1)). The anodic peak potential of the Pd/Gr(0.3)C(0.7) was 120 mV more negative than that of the Pd/C and 70 mV more negative than that of the Pd/Gr. Scanning electron microscopy images indicated that the spherical C particles accumulated on the wrinkled graphene surfaces to form C cluster/Gr hybrids having three-dimensional nanostructures. X-ray photoelectron spectroscopy data confirmed the interaction between the Pd metal and the binary Gr-C support. The Pd/Gr(0.3)C(0.7) also exhibited high stability, and so is a promising candidate for the fabrication of anodes for direct formic acid fuel cells. This work demonstrates a simple and cost-effective method for improving the performance of Pd-based electrocatalysts, which should have potential industrial applications. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.