Constructing reconstruction-inhibited nickel selenide electrocatalysts via incorporating Ag single atom for durable and efficient water oxidation

Transition-metal selenides exhibit excellent catalytic activity towards oxygen evolution reaction (OER), but suffering from serious performance degradation due to the surface reconstruction during OER. Herein, we found that the incorporation of Ag single atoms in NiSe 2 electrocatalyst (Ag SA -NiSe 2 ) could suppress the surface reconstruction, improving both catalytic activity (179 mV@10 mA cm −2 ) and stability (500 h @ ∼100 mA cm −2 ) for OER in 1.0 M KOH. The aberration corrected transmission electron microscope and X-ray absorption structure analysis reveal the co-existence of the Ag single atoms and Se vacancies in NiSe 2 matrix. In-situ Raman spectroscopy demonstrates that the introduction of single-atom Ag and Se vacancies in NiSe 2 successfully inhibits the formation of NiOOH species on the surface during OER, accounting for the excellent stability. The theoretical calculation result indicates that the Ag single atom and Se vacancies in NiSe 2 synergistically optimizes the adsorption/desorption of OER intermediates, boosting the intrinsic activity.