Enhanced electrocatalytic N₂-to-NH₃ fixation by ZrS₂ nanofibers with a sulfur vacancy

Industrially, large-scale NH3 production is achieved by the Haber-Bosch process, which operates under harsh reaction conditions with abundant energy consumption and CO2 emission. Electrochemical N2 reduction is an eco-friendly and energy-saving method for artificial N2 to NH3 fixation under ambient reaction conditions. Herein, we demonstrate that ZrS2 nanofibers with a sulfur vacancy (ZrS2 NF-Vs) behave as an efficient electrocatalyst for ambient N2 reduction to NH3 with excellent selectivity. In 0.1 M HCl, this ZrS2 NF-Vs catalyst attains a large NH3 yield of 30.72 μg h-1 mgcat.-1 and a high faradaic efficiency of 10.33% at -0.35 V and -0.30 V vs. reversible hydrogen electrode, respectively. It also shows high electrochemical and structural stability. The density functional theory calculations reveal that the introduction of Vs facilitates the adsorption and activation of N2 molecules.