Construction of nickel sulfide phase-heterostructure for alkaline hydrogen evolution reaction

Constructing transitionmetalsulfides (TMSs) heterostructure is an effective strategy to optimize the catalytic performance for hydrogen evolution reaction (HER) in alkaline medium. Herein, the rhombohedral nickel sulfide/hexagonal nickel sulfide (r-NiS/h-NiS) catalysts with the NiS phase-heterostructure were successfully fabricated by a simple one pot method. The r-NiS/h-NiS (1.25) (1.25 means the theoretical mole ratio of S and Ni added to reaction) displayed the excellent HER performance with low overpotential (101 ± 1 mV@10 mA cm^-2) and small Tafel slope (62.10 ± 0.1 mV dec^-1), which were superior to the pure phase r-NiS and h-NiS. In this work, the improved HER catalytic performances were attributed to the dense coupling interfaces between the r-NiS and h-NiS. This work shows the feasibility of construction NiS phase-heterostructure and provides a novel strategy for the application of NiS for water splitting.