Hydrogen-assisted activation of N_(2)molecules on atomic steps of ZnSe nanorods

Electrochemical reduction reaction of nitrogen(NRR)offers a promising pathway to produce ammonia(NH_(3))from renewable energy.However,the development of such process has been hindered by the chemical inertness of N_(2).It is recently proposed that hydrogen species formed on the surface of electrocatalysts can greatly enhance NRR.However,there is still a lack of atomiclevel connection between the hydrogenation behavior of electrocatalysts and their NRR performance.Here,we report an atomistic understanding of the hydrogenation behavior of a highly twinned ZnSe(T-ZnSe)nanorod with a large density of surface atomic steps and the activation of N_(2)molecules adsorbed on its surface.Our theoretical calculations and in situ infrared spectroscopic characterizations suggest that the atomic steps are essential for the hydrogenation of T-ZnSe,which greatly reduces its work function and efficiently activates adsorbed N_(2)molecules.Moreover,the liquid-like and free water over T-ZnSe promotes its hydrogenation.As a result,T-ZnSe nanorods exhibit significantly enhanced Faradaic efficiency and NH3 production rate compared with the pristine ZnSe nanorod.This work paves a promising way for engineering electrocatalysts for green and sustainable NH3 production.