Dual-Descriptor Tailoring: The Hydroxyl Adsorption Energy-Dependent Hydrogen Evolution Kinetics of High-Valance State Doped Ni3N in Alkaline Media

The requirement of both water discharge and hydrogen adsorption free energy restricts the activity of most electrocatalysts for hydrogen evolution reaction (HER) in alkaline medium. Herein, the dual-descriptor-guided design without time-consuming transition-state calculations is proposed. Theory-driven precise surface reactivity tailoring of Ni3N is demonstrated toward the balance of hydrogen and hydroxyl species adsorption energetics. The results reveal that the rate-determining step of the Ni3N catalyst mainly originates from the strong hydrogen adsorption. By higher valance-state Mo, W, and V doping, the electronic structure of Ni3N is modulated, leading to lower surface reactivity and favorable hydrogen adsorption/desorption thermodynamics. Notably, Mo-doped Ni3N exhibits optimal hydroxyl adsorption energy and fast water discharge kinetics, while W doping leads to hydroxyl poisoning and sluggish kinetics of water discharge. The experimental investigations confirm the theoretical prediction, and Mo-Ni3N realizes about 12-fold, 9-fold, and 3-fold enhancement in alkaline HER activity compared to pure Ni3N, W-Ni3N, and V-Ni3N, respectively. This dual-descriptor-guided design opens up opportunities for developing superior alkaline HER electrocatalysts.