Design of XS₂ (X = W or Mo)‐Decorated VS₂ Hybrid Nano‐Architectures with Abundant Active Edge Sites for High‐Rate Asymmetric Supercapacitors and Hydrogen Evolution Reactions

Abstract

Two-dimensional layered transition metal dichalcogenides have emerged as promising materials for supercapacitors and hydrogen evolution reaction (HER) applications. Herein, the molybdenum sulfide (MoS₂ )@vanadium sulfide (VS₂ ) and tungsten sulfide (WS₂ )@VS₂ hybrid nano-architectures prepared via a facile one-step hydrothermal approach is reported. Hierarchical hybrids lead to rich exposed active edge sites, tuned porous nanopetals-decorated morphologies, and high intrinsic activity owing to the strong interfacial interaction between the two materials. Fabricated supercapacitors using MoS₂ @VS₂ and WS₂ @VS₂ electrodes exhibit high specific capacitances of 513 and 615 F g^- ¹ , respectively, at an applied current of 2.5 A g^- ¹ by the three-electrode configuration. The asymmetric device fabricated using WS₂ @VS₂ electrode exhibits a high specific capacitance of 222 F g^- ¹ at an applied current of 2.5 A g^- ¹ with the specific energy of 52 Wh kg^- ¹ at a specific power of 1 kW kg^- ¹ . For HER, the WS₂ @VS₂ catalyst shows noble characteristics with an overpotential of 56 mV to yield 10 mA cm^- ² , a Tafel slope of 39 mV dec^-1 , and an exchange current density of 1.73 mA cm^- ² . In addition, density functional theory calculations are used to evaluate the durable heterostructure formation and adsorption of hydrogen atom on the various accessible sites of MoS₂ @VS₂ and WS₂ @VS₂ heterostructures.