The enhanced electrocatalytic activity and stability of NiW films electrodeposited under super gravity field for hydrogen evolution reaction

NiW films as cathode materials for hydrogen evolution reaction (HER) were electrodeposited under various gravity conditions. The morphologies of NiW films were characterized by SEM. Tafel curves and electrochemical impedance spectroscopy (EIS) were determined to study the electrocatalytic activity and stability of NiW films for HER in 10% NaOH solution. The results indicated that NiW films electrodeposited under normal gravity condition consisted of cellular grains and microcracks. Both surface morphologies and electrocatalytic activities of NiW films were not improved obviously by adjusting solution composition and current density. However, NiW films with fine grains and fewer microcracks were electrodeposited under super gravity field. The electrocatalytic activities of NiW films for HER increased with gravity coefficient (G) value. Meanwhile, NiW films showed excellent stability. During shut-down electrolysis, corrosion resistances of NiW film electrodeposited under G value of 256 were always higher than those of NiW film electrodeposited under normal gravity condition.