Construction of sheet-on-sheet hierarchical MoS2/NiS2 heterostructures as efficient bifunctional electrocatalysts for overall water splitting

Design and construction of low-cost bifunctional catalysts with excellent activity and stability is vital for water splitting. Herein, a strategy to construct bifunctional sheet-on-sheet hierarchical MoS2/NiS2 heterostructures in-situ grown onto carbon cloth (CC) for water splitting was proposed. Benefitting from the abundant heterogeneous interfaces, rich defects, fully exposed active sites, and electronic interaction, the as-obtained optimal MoS2/NiS2/CC catalyst exhibits superior electrochemical activity and durability toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Specifically, current densities of 10, 50, and 100 mA cm−2 can be reached at overpotentials of 80, 142, 175 and 303, 348, 384 mV for HER and OER, respectively. More importantly, when assembled as both cathode and anode for overall water splitting, a low cell voltage of 1.63 V is required to achieve a current density of 10 mA cm−2, demonstrating that MoS2/NiS2/CC is a promising candidate for water splitting. In brief, this study provides a new approach to develop highly efficient bifunctional electrocatalysts.