Enhanced electrocatalytic activity of Pt nanoparticles supported on functionalized graphene for methanol oxidation and oxygen reduction

Abstract

Reduced graphene oxide (RGO) is modified with 1,1′-dimethyl-4,4′-bipyridinium dichloride (methyl viologen, i.e. MV) by a π–π interaction, and further used as support for immobilization of Pt nanoparticles to prepare a Pt/MV–RGO catalyst for direct methanol fuel cells. Transmission electron microscopy, X-ray powder diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy are used to characterize the morphology and microstructure of the prepared catalyst. Electrocatalytic performance of the as-prepared Pt/MV–RGO hybrid is investigated by cyclic voltammetry, linear scan voltammetry, COads stripping voltammetry and electrochemical impedance spectroscopy. The Pt/MV–RGO hybrid exhibits much higher catalytic activities than Pt/RGO toward both methanol oxidation and oxygen reduction, suggesting that Pt/MV–RGO hybrid could be a promising electrocatalyst for high-performance direct methanol fuel cells applications.