In-Plane Co9S8@MoS2 Heterostructure for Hydrogen Evolution Reaction in Alkaline Media
Transition metal sulfides have emerged as a promising hydrogen evolution reaction (HER) electrocatalyst in acidic media due to high intrinsic activity. They exhibit inferior HER activity in alkaline media, however, owing to the sluggish water dissociation kinetics. Herein, in-plane MoS2/Co9S8 heterostructures are in situ grown on three-dimensional carbon network substrates with interconnected hierarchical pore by one-step pyrolysis to enhance the alkaline HER activity. The experiment results reveal that the HER kinetic of MoS2 is accelerated after construction of heterostructures. The synthesized MoS2/Co9S8 heterostructures anchored on three-dimensional interconnected hierarchical pore carbon network exhibits a lower overpotential of 177 mV than MoS2 (252 mV) at 10 mA cm−2 for HER in 1M KOH. The enhanced catalytic performance is mainly attributed to the accelerated water dissociation kinetics on the interface of MoS2 and Co9S8. In combination with DFT calculations, it reveals that assemble the interfaces construction synergistically favor the chemisorption of proton and cleavage of the O-H bonds of the H2O molecule, thus accelerating the kinetics of the HER. Moreover, the three-dimensional interconnected hierarchical pore carbon (3DC) network structure is beneficial for the circulation of the electrolyte and H2 spill over. This study enables the present strategy as a facile route for fabricating efficient HER catalysts.