PdxAuy loaded reduced graphene oxide on nickel foam(PAGN) composite for high efficient methanol and ethanol electrooxidation

Abstract

PdxAuy loaded reduced graphene oxide on nickel foam(PAGN) were synthesized in a simple and green way of spontaneous reduction. Different characterization methods, including XRD, Raman spectra, SEM, TEM and XPS, were used to investigated the chemical composition, morphology and structure of the composites. The catalytic activity of the prepared electrodes were estimated by means of cyclic voltammetry(CV), chronoamperometry(CA), and electrochemical impedance spectroscopy(EIS). Graphene oxide was firstly reduced by Ni foam directly, and then noble metal(Pd and Au) ions were reduced by reduced graphene oxide supported on the surface of Ni substrate. By varying the palladium/gold mole ratios into 4:1, 5:1 and 6:1, the optimized P5A1GN anode with a ratio of 5:1 is obtained in terms of the best performance among all these anodes. The P5A1GN electrode exhibited respectively the maximum peak current density of 0.72 and 1.18A cm−2mg−1PdAu in methanol and ethanol electrooxidation, which only reduced by 1% and 7% after a long-term CV scanning test of 1000 cycles. The better overall performance and stability of the P5A1GN electrode in methanol and ethanol oxidation was ascribed to the improvement of graphene to the electrode properties, the optimization of Pd electronic properties tuned by Au element as well as the cocatalysis of Au.