Polyol synthesized graphene/PtxNi100-x nanoparticles alloy for improved electrocatalytic oxidation of methanol in acidic and basic media

Abstract In this study, a series of graphene-supported Pt–Ni nanoparticles are successfully synthesized by a simple modified polyol method and used as electrocatalysts for methanol oxidation. In this method, graphene oxide is reduced to graphene and Pt–Ni alloy nanoparticles are deposited on graphene sheets simultaneously in ethylene glycol, which acts as a reducing agent. The electrocatalysts are physically characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM). The cyclic voltammetry and chronoamperometry electrochemical measurements in acidic and alkaline media are promising. The electrocatalysts containing Ni (G/Pt75–Ni25, G/Pt54–Ni46 and G/Pt40–Ni60) have higher catalytic activity and stability for the MOR than pure G/Pt in both acidic and alkaline media. G/Pt54–Ni46 has the highest performance in acidic and alkaline media, and its activity in alkaline media (2732 A/gPt) is nearly 10 times higher than that in acidic media (260 A/gPt). The superior catalytic performance in alkaline media may be because Ni is more stable in alkaline media. These electrocatalysts are promising candidates for direct methanol fuel cell (DMFC) anode catalysts.