Water Dissociation Kinetic-Oriented Design of Nickel Sulfides via Tailored Dual Sites for Efficient Alkaline Hydrogen Evolution

The reaction kinetics of alkaline hydrogen evolution reactions (HER) is a trade-off between adsorption and desorption for intermediate species (H2O, OH, and H-ads). However, due to the complicated correlation between the intermediates adsorption energy and electronic states, targeted regulating the adsorption energy at the atomic level is not comprehensive. Herein, nonmetals (B, N, O, and F) are used to modulate the adsorption energy and electronic structure of Ni3S4, and propose that H2O and OH adsorption energy are correlate directly with d-band center (epsilon(d)) of transition metal Ni, and H-ads adsorption energy has a linear dependence on p-band center (epsilon(p)) of nonmetal S. Direct experimental evidence is offered that in all nonmetals doping samples, Tafel slope and exchange current density can be improved regularly with the epsilon(d) and epsilon(p), and F-Ni3S4 shows the optimum activity with tiny overpotential 29 and 92 mV for harvesting current density 10 and 100 mA cm(-2), respectively. Furthermore, the micro-kinetics analysis and density functional theory calculations verify that F-doping can efficiently reduce the energy barrier of the Volmer step, eventually accelerating the HER kinetics. This work provides atomic-level insight into the structure-properties relationship, and opens an avenue for kinetic-oriented design of alkaline HER and beyond.

Automated summary

The study investigates the modulation of adsorption energy and electronic structure of a catalyst surface using nonmetal elements, showing a correlation between adsorption energy and metal and nonmetal centers to enhance current density and activity. Experimental evidence demonstrates that F-doping can accelerate reaction kinetics, providing new insights for the design of alkaline hydrogen evolution reactions.