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 NiSe2 electrocatalyst (AgSA-NiSe2) 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 NiSe2 matrix. In-situ Raman spectroscopy demonstrates that the introduction of single-atom Ag and Se vacancies in NiSe2 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 NiSe2 synergistically optimizes the adsorption/desorption of OER intermediates, boosting the intrinsic activity. [Display omitted] •A novel self-supported AgSA-NiSe2 single atom catalyst was fabricated.•AgSA-NiSe2 shows excellent OER activity (179 mV@10 mA cm−2) in 1 M KOH.•AgSA-NiSe2 exhibits excellent durability with barely degradation for 500 h@100 mA cm−2.•Single-atom Ag and Se vacancies suppresses the surface reconstruction of NiSe2.•The catalytic mechanism at an atomic-scale insight is uncovered by DFT.