Three-dimensional Au0.5/reduced graphene oxide/Au0.5/reduced graphene oxide/carbon fiber electrode and its high catalytic performance toward ethanol electrooxidation in alkaline media

A three-dimensional Au nanoparticle/reduced graphene oxide (RGO)/carbon fiber (CF) hybrid electrode (denoted as Au-0.5/RGO/Au-0.5/RGO/CF) was fabricated via a layer-by-layer method. The as-formed composite was characterized by Raman spectrometry, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectrometry. Two RGO sheets and two Au nanoparticle sheets were assembled in alternate layers on the CFs. The catalytic performance of the as-prepared electrode was evaluated via cyclic voltammetry and chronopotentiometry. The as-synthesized three-dimensional Au-0.5/RGO/Au-0.5/RGO/CF electrode showed highly efficient electrocatalytic activity toward ethanol oxidation in alkaline medium and the Au nanoparticles were not affected by the graphene layers. The synergistic interaction between the RGO sheets and Au nanoparticles enhanced the catalytic activity of the electrode. The excellent electronic conductivity of the RGO sheets benefited electron transfer and the removal of the intermediate species by oxidation during the ethanol electrooxidation reaction, which improved the catalytic activity. As a result of the effects of these multiple factors, the Au-0.5/RGO/Au-0.5/RGO/CF electrode displayed a good catalytic performance.