High electrocatalytic performance of a graphene-supported PtAu nanoalloy for methanol oxidation

Homogeneously distributed PtAu nanoalloy anchored to graphene (PtAuNA/G) was synthesized via a simple one-step electrochemical deposition process, in which Pt and Au ions and graphene oxide was simultaneously electro-reduced on the glassy carbon electrode. The morphology evolution of PtAuNA/G synthesized with different deposition times was characterized via field-emission scanning electron microscopy. X-ray diffraction and transmission electron microscopy was applied to confirm the alloy structure. The electrodeposition conditions, including the deposition time, were further optimized to explore the morphological evolution of PtAuNA/G. Based on cyclic voltammetry and chronoamperometry results, it was found that PtAuNA/G can efficiently catalyze the oxidation of methanol in alkaline media with dramatically enhanced electrocatalytic activity (7.268 mA cm−2, 3.83 times higher than that of commercial carbon-supported Pt nanoparticles, 1.894 mA cm−2), along with a considerably improved tolerance to poisoning (current decline: 69% vs 99.89%). These results indicate a great potential for PtAuNA/G in fabricating high-performance direct methanol fuel cells.