Interfacial coupling of NiSe in heterostructures promotes electrocatalytic hydrolysis of MoS₂

Molybdenum sulfide (MoS₂) has attracted much attention as a potential catalyst for the oxygen evolution reaction (OER), but its unique low activity and low edge active centers limit its electrocatalytic activity. In this study, catalysts were prepared by growing NiSe nanoclusters in situ onto MoS₂ substrates via electrodeposition; ultrathin MoS₂ nanosheets and NiSe nanoclusters were cross-linked with each other to form a unique three-dimensional rosette structure; and MoS₂@NiSe catalysts were successfully synthesised, which significantly improved bifunctional catalytic performance. The synthesised MoS₂@NiSe catalysts exhibited good electrochemical performance: overpotentials required to satisfy the HER and OER processes at a current density of 10 mA cm^-2 in 1 M KOH were 80 mV and 254 mV, respectively. When applied as a cathode and anode to assemble a bifunctional electrode system, the MoS₂@NiSe||MoS₂@NiSe electrolytic cell system required only 1.54 V to achieve 10 mA cm^-2 in an alkaline electrolyte, which exceeded the value of most of the bifunctional catalysts reported in the literature to date. In addition, the catalyst maintained good surface structure and catalytic performance after a 24 h stability test. This study provides a new idea for the improvement and design of MoS₂-based bifunctional catalysts and provides an important reference for research in the field of clean energy.