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

A well-defined Ni-Ni(OH)2 epitaxial interface boosts alkaline hydrogen evolution: enhanced the adsorption of H2O reactants, accelerated the cleavage of H-OH bonds and improved hydrogen desorption kinetics. [Display omitted] 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.