Hollow core-shell NiCo2S4@MoS2 dodecahedrons with enhanced performance for supercapacitors and hydrogen evolution reaction

The development of bifunctional electrochemically-active micro-/nanomaterials with heterostructures for both supercapacitors and hydrogen evolution reaction (HER) enables the possibility to integrate energy storage and conversion into one single system. Herein, heterostructural NiCo2S4@MoS2 materials have been successfully prepared using zeolitic imidazolate frameworks as templates, including transformation to bimetallic layered double hydroxide, and sequential sulfuration. The smart process entails an assembly of MoS2 nanosheets on NiCo2S4 nanobuilding blocks with hollow core-shell nanoarchitectures. Specifically, when tested as an electrode in a supercapacitor, it can deliver an increased specific capacitance of 860 F g(-1) at a current density of 1 A g(-1), superior rate capability and cyclic stability. Furthermore, the NiCo2S4@MoS2 heterostructure also efficiently electrocatalyzes the HER in an alkaline electrolyte with a low overpotential of 194 mV, a favorable HER kinetics and better long-term stability. Results of both scenarios attest to the enhanced electrochemical performance of the NiCo2S4@MoS2 heterostructure compared to its NiCo2S4 counterpart, which is attributed to the hollow porous core-shell structures, nanointerface engineering and the synergistic effect between NiCo2S4 and MoS2. This work will broaden our horizons in designing and fabricating multifunctional active materials for next generation energy storage and conversion applications.