Accelerated water dissociation kinetics by nickel-nickelous hydroxide epitaxial interfaces for superior alkaline hydrogen generation

The intrinsic performance of an electrocatalyst can be reinforced by constructing appropriate epitaxial interfaces, where the modulated electronic states and adsorption/desorption behaviors are conductive to enhancing electrocatalytic activity. Herein, nickel-nickelous hydroxide epitaxial interface supported on nickel foam (Ni-Ni(OH)₂/NF) with epitaxial growth of nickel nanoparticles on the surface of nickelous hydroxide nanoribbons is devised for alkaline hydrogen evolution reaction (HER). Notably, the Ni-Ni(OH)₂/NF reveals excellent electrocatalytic activity of alkaline HER (158 mV @ 100 mA cm⁻²), along with robust stability (90 % activity retention after 150 h continuous test at 200 mA cm⁻²). Theoretical simulations disclose the tuned interface electronic structure and accelerated water dissociation around the epitaxial nickel-nickelous hydroxide interface result in efficient electrochemical activity toward alkaline hydrogen evolution.