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Alkali-water electrolyzers and hydroxide exchange membrane fuel cells are emerging as promising technologies to realize hydrogen economy.Developing cost-effective electrode materials with high activities towards corresponding hydrogen evolution (HER) and oxidation (HOR) reactions plays a crucial role in commercial hydrogen production and utilization.Herein,we fabricated a Ⅴ-doped Ni3N/Ni heterostructure (V-Ni3N/Ni) through a controlled nitridation treatment on a V-incorporated nickel hydroxide precursor.The resultant catalyst exhibits comparable catalytic activity and durability to commercial Pt/C in terms of both HER (a low overpotential of 44 mV at the current density of 10 mA·cm-2) and HOR (a high current density of 1.54 mA·cm-2 at 0.1 V versus reversible hydrogen electrode) under alkaline conditions.The superior activity of V-Ni3N/Ni grown on different substrates further implies its intrinsic performance.Density functional theory (DFT) calculations reveal that the coupled metallic Ni and doped V can promote the water adsorption,accelerate the Volmer step of alkaline HER,as well as optimize the adsorption and desorption of hydrogen intermediate (H·) to reach a balanced △GH· value.