Proton-induced fast preparation of size-controllable MoS2 nanocatalyst towards highly efficient water electrolysis

Abstract MoS2 has emerged for catalyzing the hydrogen evolution reaction. Various notable strategies have been developed to downsize the MoS2 particles and expose more active edges. However, the restacking issue, which reduces the exposure degree, has rarely been taken into account. Herein, we report on a facile proton-induced fast hydrothermal approach to produce size-controllable MoS2 nanocatalysts and demonstrate that along the varying of sheet sizes, there is a trade-off between the intrinsic catalytic activity (mainly determined by the unsaturated sulfur on the sheet edges) and the active edge accessibility (influenced by the assembly structure). The size-optimized catalyst delivers a high performance of a low overpotential of ∼200 mV at 10 mA/cm2, a Tafel slope of 46.3 mV/dec, and a stable working state, which is comparable to the recent notable works. Our findings will provide a pathway for its large-scale application and enhance the water electrolysis performance.