Low-cost preparation method of well dispersed gold nanoparticles on reduced graphene oxide and electrocatalytic stability in PEM fuel cell

Abstract

A facile and feasible protocol for synthesis of functionalized reduced graphene oxide decorated with gold nanoparticles (AuNP/rGO) in mild reaction conditions has been successfully developed. Starting from graphite, the following synthesis routes were developed: (1) preparation of graphite oxide; (2) graphene oxide (GO) functionalized with a compatible polymer; (3) reduced graphene oxide decorated with gold nanoparticles (final compound). The surface morphology of as-prepared AuNP/rGO was investigated using scanning electron microscopy (SEM) and specific surface area was determined using BET method, while structural properties were investigated using Raman scattering spectroscopy, X-Ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR). This comprehensive study demonstrated the simultaneous reduction of GO and the achievement of Au nanoparticles dispersed on graphene sheets. An ORR catalytic system containing prepared AuNP/rGO was developed, and electrochemical measurements were performed. Firstly, the ex-situ electrochemical performances of AuNP/rGO-modified carbon electrode were investigated using cyclic voltammetry. Secondly, the in-situ electrochemical evaluation were carried out as application in real PEM fuel cell and analyzed as comparison commercial Pt/C versus developed ORR catalytic system. The in-situ CV results showed that the oxidation and reduction peaks corresponding to hydrogen adsorption/desorption decreased differently, indicating that a decrease of electrochemical surface area occurs for both cases, more visible for commercial catalyst. The cathode made with AuNP/rGO developed in this work, tested in hydrogen-air PEMFC, had a power density of 0.59 W cm − 2 at 0.6 V, a meaningful voltage for fuel cells operation, comparable with that of a commercial Pt-based cathode tested under identical conditions, but a superior electrochemical stability. The results confirmed that the developed AuNP/rGO nanoparticles could be valuable alternative ORR nanostructured electrodes. Keywords: Graphene, Reduced graphene oxide, Au nanoparticles, PEMFC