Defect chemistry of NiS for oxygen evolution reaction

Transition metal compounds are considered to be one of the most feasible materials for electrocatalytic oxygen evolution. However, to fabricate highly active OER electrocatalysts, rational design of simple and effective strategies is still required. Herein, through hydrogen etching, we synthesizes defect-rich NiS with excellent catalytic performance for oxygen evolution, where it shows a low overpotential of 444 mV at 50 mA cm−2, and a small Tafel slope of 48.32 mV dec−1. Importantly, the characterization results implies that the NiS exhibits dynamic remodeling during the OER process to form NiOOH in situ. This work provides an effective strategy for transition metal compounds to enhance OER performance.