Orderly Nanodendritic Nickel Substitute for Raney Nickel Catalyst Improving Alkali Water Electrolyzer

Abstract The development of nonprecious metal catalysts to meet the activity‐stability balance at industrial‐grade large current densities remains a challenge toward practical alkali‐water electrolysis. Here, this work develops an orderly nanodendritic nickel (ND‐Ni) catalyst that consists of ultrafine nanograins in chain‐like conformation, which shows both excellent activity and robust stability for large current density hydrogen evolution reaction (HER) in alkaline media, superior to currently applied Raney nickel (R‐Ni) catalyst in commercial alkali‐water electrolyzer (AWE). The ND‐Ni catalyst featured by a three‐dimensional (3D) interconnecting microporous structure endows with high specific surface area and excellent conductivity and hydrophilicity, which together afford superior charge/mass transport favorable to HER kinetics at high current densities. An actual AWE with ND‐Ni catalyst demonstrates durable water splitting with 1.0 A cm⁻² at 1.71 V under industrial conditions and renders a record‐low power consumption of 3.95 kW h Nm⁻³ with an energy efficiency close to 90%. The hydrogen price per gallon of gasoline equivalent (GGE) is calculated to be ≈$0.95, which is less than the target of $2.0 per GGE by 2026 from the U.S. Department of Energy. The results suggest the feasibility of ND‐Ni substitute for R‐Ni catalyst in commercial AWE.