Nanostructured Porous Gold for Methanol Electro-Oxidation

Abstract

Dealloying single phase alloys is known to generate a type of nanostructured porous metals with intriguing properties. In this study, nanoporous gold (NPG) made by dealloying Au−Ag is investigated as a novel electrode material for methanol electro-oxidation. Compared to bulk Au electrode, oxidation and subsequent reduction of NPG occur at significantly negative potentials in both acid and alkaline solutions. NPG shows great catalytic activity for methanol electro-oxidation, but the structure quickly coarsens upon long time potential cycling. Interestingly, after surface modification with only a tiny amount of platinum, NPG exhibits greatly enhanced electrocatalytic activity toward methanol oxidation in the alkaline solutions, which is exemplified by a broad and high anodic peak during the positive scan and two secondary oxidation peaks in the subsequent reverse scan. At the same time, SEM observation and long-time potential cycling both prove that Pt−NPG has much enhanced structure stability as compared with bare NPG.