Three-dimensional functionalized graphene networks modified Ni foam based gold electrode for sodium borohydride electrooxidation

• 3D RGNA was prepared by a “dipping, electroreduction and electrodeposition” process.
• RGNA exhibits good stability and high electrocatalytic activity for NaBH4 oxidation.
• The high specific surface area, electric conductivity, and hydrogen storage property of graphene lead to a super catalytic activity.

Three-dimensional (3D) reduced graphene networks (RGN) were successfully fabricated on Ni foam without any conductive agents and polymer binders by dipping commercial Ni foam into graphene oxide (GO) suspension and subsequent a electroreduction process in a buffer solution. Au nanoparticles were then deposited on the RGN through an electrodeposition process to form a novel reduced graphene networks-Au (RGNA) electrode. The morphology and phase structure of the RGNA electrode are characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction spectrometer. The NaBH4 electrooxidation performance on the RGNA electrode is investigated by means of cyclic voltammetry and chronoamperometry. The RGNA electrode owns special hierarchical porous structure, rapid electron and ion transport, and large electroactive surface area due to the intrinsic electronic conductivity, mesoporous nature of graphene. The RGNA electrode exhibits a good stability during the electrochemical process and the oxidation current density at RGNA electrode reached 500 mA cm−2 at 0 V in the solution containing 0.1 mol dm−3 NaBH4 and 2 mol dm−3 NaOH, which is higher than that at bare Au–Ni foam without graphene. The excellent structural stability and high catalytic performance for NaBH4 electrooxidation make the RGNA a promising material for future energy systems.