Vanadium Substitution Steering Reaction Kinetics Acceleration for Ni₃N Nanosheets Endows Exceptionally Energy-Saving...

Designing highly active transition-metal-based electrocatalysts for energy-saving electrochemical hydrogen evolution coupled with hydrazine oxidation possesses more economic prospects. However, the lack of bifunctional electrocatalysts and the absence of intrinsic structure-property relationship research consisting of adsorption configurations and dehydrogenation behavior of N₂H₄ molecules still hinder the development. Now, a V-doped Ni₃N nanosheet self-supported on Ni foam (V-Ni₃N NS) is reported, which presents excellent bifunctional electrocatalytic performance toward both hydrazine oxidation reaction (HzOR) and hydrogen evolution reaction (HER). The resultant V-Ni₃N NS achieves an ultralow working potential of 2 mV and a small overpotential of 70 mV at 10 mA cm^-2 in alkaline solution for HzOR and HER, respectively. Density functional theory calculations reveal that the vanadium substitution could effectively modulate the electronic structure of Ni₃N, therefore facilitating the adsorption/desorption behavior of H* for HER, as well as boosting the dehydrogenation kinetics for HzOR.