This study reports the development of a MoNi4 electrocatalyst supported by MoO2 cuboids on nickel foam (MoNi4/MoO2@Ni) for efficient hydrogen evolution reaction (HER) in alkaline solutions. The catalyst is designed to accelerate the sluggish water dissociation kinetics (Volmer step) through controlling the outward diffusion of nickel atoms on annealed NiMoO4 cuboids. Experimental and theoretical results confirm that the MoNi4/MoO2@Ni catalyst exhibits zero onset overpotential, a low overpotential of 15 mV at 10 mA cm−2, and a low Tafel slope of 30 mV per decade in 1 M potassium hydroxide electrolyte. These properties are comparable to those of platinum (Pt) catalysts and superior to state-of-the-art platinum-free electrocatalysts. The catalyst's scalability and stability make it promising for practical water-alkali electrolyzers.This study reports the development of a MoNi4 electrocatalyst supported by MoO2 cuboids on nickel foam (MoNi4/MoO2@Ni) for efficient hydrogen evolution reaction (HER) in alkaline solutions. The catalyst is designed to accelerate the sluggish water dissociation kinetics (Volmer step) through controlling the outward diffusion of nickel atoms on annealed NiMoO4 cuboids. Experimental and theoretical results confirm that the MoNi4/MoO2@Ni catalyst exhibits zero onset overpotential, a low overpotential of 15 mV at 10 mA cm−2, and a low Tafel slope of 30 mV per decade in 1 M potassium hydroxide electrolyte. These properties are comparable to those of platinum (Pt) catalysts and superior to state-of-the-art platinum-free electrocatalysts. The catalyst's scalability and stability make it promising for practical water-alkali electrolyzers.