The 3D core–shell heterostructure catalysts by CoNiS nanosheets interfacial assembled on CuO nanorods for efficient water electrolysis

Abstract The development of high-efficiency electrocatalysts is one of the important ways to mass-produce hydrogen but still confronts many challenges. Herein, a 3D core–shell heterostructure catalyst is rationally designed by interfacial assembled of CoNiS nanosheets on CuO nanorods (CuO@CoNiS NRs). The 3D core–shell heterostructure significantly increases the electrochemical surface area, enabling more active centers to be exposed and facilitating the charge transfer, thus boosting catalytic activity. The catalyst requires low overpotential for HER (96 mV) and OER (246 mV) to achieve 10 mA cm−2 in 1 M KOH. It is capable of attaining 200 mA cm−2 with only 206 mV for HER and achieving 100 mA cm−2 with 314 mV for OER. Meanwhile, CuO@CoNiS NRs as a water electrolyzer to generate 10 mA cm−2 requires a low voltage of 1.52 V. This work provides an effective strategy for developing efficient non-noble metal catalysts by reasonable construction of nanostructure and heterogeneous interface.