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

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/Pt-75-Ni-25, G/Pt-54-Ni-46 and G/Pt-40-Ni-60) have higher catalytic activity and stability for the MOR than pure G/Pt in both acidic and alkaline media. G/Pt-54-Ni-46 has the highest performance in acidic and alkaline media, and its activity in alkaline media (2732 A/g(p)(t)) is nearly 10 times higher than that in acidic media (260 A/g(p)(t)). 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.