Synthesis of Pt, PtRh, and PtRhNi Alloys Supported by Pristine Graphene Nanosheets for Ethanol Electrooxidation

Ultrafine Pt, PtRh, and PtRhNi particles were assembled on pristine graphene nanosheets (GNSs), and the resulting hybrids were examined as electrocatalysts for ethanol oxidation. The structures of the catalysts were characterized by using transmission electron microscopy and X-ray diffraction. The bulk composition of the catalysts was determined by using energy-dispersive X-ray spectroscopy, and the surface composition of the nanoparticles was analyzed by using X-ray photoelectron spectroscopy. The activity of the catalysts for ethanol electrooxidation was studied by using cyclic voltammetry, linear sweeping voltammetry, and chronoamperometry. The activity of the catalysts followed the order of Pt/GNS < PtRh/GNS < PtRhNi/GNS, and it was well correlated with the structural characteristics of the catalysts. The excellent activity and stability of the PtRhNi/GNS catalyst was attributed to the bifunctional effects as well as the modification of Pt electronic structures.