A general strategy for even growth of ultrasmall MoS2 nanosheets on carbon supports to boost hydrogen evolution activity

MoS₂ has been considered as a potential replacement for Pt-based catalysts in hydrogen evolution reaction. But the lack of sufficient active sites limits the intrinsic activity of MoS₂-based catalysts. Here, we propose a general strategy to synthesize ultra-small MoS₂ nanosheets grown evenly on carbon substrates to maximize the active sites by exposing more edge positions and inducing MoS₂ phase transition. It is found that Ru can assist MoS₂ to grow vertically and uniformly on the surface of carbon substrates by in situ derivatization to improve the catalytic activity effectively. MoS₂ nanosheets on the substrates are much smaller and denser than those prepared without Ru or with other metal elements. Electrocatalysis results revealed that the number of active sites and conductivity of the optimized Ru-MoS₂@CSs increase obviously, and the overpotential at 10 mA cm⁻² is much lower than that of MoS₂@CSs and metal (Co, Ni)-MoS₂@CSs, respectively, at 1.0 M KOH.