Mo-doped Ni3S2 nanosheet arrays for boosting hydrogen evolution activity and supercapacitor energy storage

The design and preparation of bifunctional electrode materials play a vital role in the field of energy storage and conversion. Herein, Mo-doped Ni3S2 nanosheet arrays assembled on nickel foam (named as Mo-Ni3S2) are designed through three-step continuous hydrothermal methods for enhanced hydrogen evolution reaction (HER) and supercapacitor storage characteristics. The ultrathin Mo-Ni3S2 nanosheets structure could modulate electronic structure and offer rich actives sites, thereby expediting the mobility of charge carriers and engendering a greater density of active sites. Consequently, the Mo-Ni3S2 exhibits low overpotential both in alkaline and acidic solution with the value of 53 and 65 mV at the current density of 10 mA cm−2, respectively. Meanwhile, the HER activity can be well maintained after 17 h of continuous operation at 10 mA cm−2, demonstrating its excellent stability. Furthermore, the as-prepared Mo-Ni3S2 as pseudocapacitive materials exhibits a specific capacitance of 3528 F g−1 at 1 A g−1, implying outstanding long durability with 96.5% capacity retention after 3000 charge–discharge cycles. Overall, this work provides a viable strategy for the development of transition metal-based materials as efficient bifunctional catalysts.