Ternary NiAuPt Nanoparticles on Reduced Graphene Oxide as Catalysts toward the Electrochemical Oxidation Reaction of Ethanol

This article presents a facile one-pot synthetic method to prepare ternary NiAuPt nanoparticles on reduced graphene oxide (rGO) nanosheets (NiAuPt-NGs) through the simultaneous chemical reduction of metal precursors and GO in solution and an investigation of NiAuPt-NGs as electrocatalysts toward ethanol oxidation reaction (EOR). The NiAuPt nanoparticles grow on the rGO sheets after the chemical reduction of their precursors. They consist of tightly coupled nanostructures of Ni, Au, and Pt, which have neither an alloy nor a core–shell structure, as revealed by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. As indicated by the Raman spectra, GO is reduced to rGO more completely in the presence of the metal precursors than in the absence of the metal precursors. The electrocatalysis of NiAuPt-NGs toward EOR in alkaline medium was investigated by cyclic voltammetry, chronoamperometry, and impedance spectroscopy. NiAuPt-NGs can effectively catalyze EOR. The ternary NiAuPt-NGs give rise to a high peak current density for EOR, which is more than 8 times higher than that on the monometallic Pt-NGs, 4 times higher than that on the bimetallic NiPt-NGs, and almost 2 times higher than that on the bimetallic AuPt-NGs. In addition, NiAuPt-NGs substantially lower the onset potential for EOR. It is −803 mV vs SHE, which suggests the excellent tolerance of NiAuPt-NGs against the residues of EOR. The high electrocatalytic activity of NiAuPt-NGs is attributed to the synergetic effect of the three nanostructured metals for EOR.