Green synthesis of graphene–PtPd alloy nanoparticles with high electrocatalytic performance for ethanol oxidation

Abstract

A facile and green method is described for the fabrication of PtPd alloy nanoparticles on graphene nanosheets (PtPdNPs/GNs). The keys of the synthesis strategy were to employ a low-cost and green solvent, ethanol, as the reductant, and a two-dimensional carbon material, GNs, as the supporting material. The morphology, structure and composition of the as-prepared PtPdNPs/GNs were characterized by transmission electron microscopy (TEM), high resolution TEM, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was found that by changing the preparation procedures and varying the molar ratio of the starting precursors, NPs with different shapes such as spherical NPs (Pt₁Pd₁NPs), nanoflowers (Pd@PtNFs) and nanodentrites (Pt₃Pd₁NPs) could be produced on GNs. Based on these observations, a plausible growth mechanism of PtPdNPs/GNs was discussed. In addition, the electrocatalytic properties of PtPdNPs/GNs for direct ethanol oxidation in alkaline media were systematically investigated. Due to the synergetic effects of Pt and Pd, and the enhanced electron transfer properties enhanced of GNs, PtPdNPs/GNs exhibited higher electrocatalytic ability and better tolerance to reaction intermediate poisoning in the electrooxidation of ethanol compared with Pt nanoflowers supported on GNs (PtNFs/GNs), PdNPs/GNs and PtPdNPs supported on carbon black (PtPdNPs/C). The presented method is a general, facile and green approach for the synthesis of GN-supported bimetallic PtM electrocatalysts, which is significant for the development of high performance electrocatalysts.