Strong electronic metal-support interaction of Ni₄Mo/N-SrMoO₄ promotes alkaline hydrogen electrocatalysis

Ni₄Mo electrocatalyst stands out as the promising candidate for hydrogen evolution/oxidation reaction (HER/HOR), yet the intensive hydrogen adsorption leads to sluggish kinetics, decreasing hydrogen catalysis efficiency. Herein, the structure of Ni₄Mo nanoparticles anchored on wafer-biscuit-like N-SrMoO₄ nanorods (Ni₄Mo/N-SrMoO₄) is developed to accelerate reaction kinetics by modulating electronic structure. The designed N-SrMoO₄ support enables strong electronic metal-support interaction with Ni₄Mo, resulting in a downward shift of d-band center and achieving thermally neutral hydrogen adsorption. Ni₄Mo/N-SrMoO₄ exhibits HER performance with an ultralow overpotential of 15 mV at 10 mA cm⁻², superior to Pt/C (η₁₀=18 mV). The outstanding exchange current density of 10.2 mA cm⁻² for HOR is three times higher than that of Pt/C (3.5 mA cm⁻²). Ni₄Mo/N-SrMoO₄ is further assembled in anion exchange membrane water electrolyzer (AEMWE), resulting in a current density of 100 mA cm⁻² at voltage of 1.71 V and the excellent stability of 300 hours. Theoretical calculations and in-situ spectroscopy indicate that the introduction of Sr in N-SrMoO₄ effectively enhances electronic metal-support interaction, facilitates the enrichment of adsorbed hydroxyl (OH_ads) on active sites and weakens hydrogen adsorption on Ni₄Mo, thereby accelerating reaction kinetics of hydrogen electrocatalysis.