Evaluation of the electrocatalytic activity and stability of graphene oxide nanosheets coated by Co/Ni elements toward hydrogen evolution reaction

Abstract

Electrocatalytic properties of a novel Graphene Oxide (GO) electrode combined with the cobalt/nickel (Co+Ni/GO) nanoparticles were investigated using Hydrogen Evolution Reaction (HER). The (Co+Ni)/GO electrode was synthesized in two steps. First, the GO nanosheets coating was pulse reverse electrodeposited from 0.5 mg ml−1 of GO suspension. Then, a coating modified by the electrochemical deposition of Co and Ni ions was obtained by the chloride salts. Microstructure, phase content, topography, and functional groups of the thin films were studied by the field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, atomic force microscopy, Fourier transform infrared spectrometer experiments, transition electron microscopy, and x-ray photoelectron microscopy. Moreover, the electrocatalytic activity of fabricated electrodes was studied using LSV and EIS while and electrocatalytic stability was evaluated via chronoamperometry test. The results demonstrated that the Tafel slope and overpotential of the electrode in the HER current density of 10 mA cm−2 are mainly decreased to 64 mV dec−1 and 200 mV versus RHE, respectively, for the (Co+Ni)/GO electrode. The suitable electro-activity and acceptable stability of the modified (Co+Ni)/GO shows that this electrode can be a good candidate in HER application.