Single-Atom-Modified MoS2 for Efficient Hydrogen Evolution

The over-reliance on fossil fuels leads to deteriorating ecological environment and motivates us to develop sustainable and clean energy alternatives in order for our long-term survival on the earth. Hydrogen energy is one of the most promising energy carriers in the 21st century since the only by-product is H2O. In comparison to steam reforming of natural gas and coal, hydrogen evolution reaction ( HER) via H2O electrolysis is a more attracting pathway for H-2 production because of the low cost, high efficiency and abundant raw materials, which would contribute to a lower carbon footprint. HER requires stable and active enough catalyst materials to overcome the reaction barriers. It is well known that Pt group materials are state-of-the-art HER catalysts, but unfortunately, the low abundance and high cost complicate its large-scale applications. The transition metal disulfides (TMDs) possess a two-dimensional layered structure and a larger specific surface area, which is conducive to expose more active sites. In particular, MoS2, a representative of TMDs, has attracted tremendous research interests in HER domain and is supposed to be a cost-affordable alternative to Pt-based catalysts. In this work, the research status of MoS2 modified by single atoms (SA-MoS2) of noble metal, non noble metal, and nonmetal, to catalyze HER reactions is reviewed. Based on the overpotential and Tafel slope, the structure-function relationship between HER performance and SA-MoS2 structures is summarized. Finally, future research directions are proposed and hopefully, this paper will guide rational design of SA-MoS2 for more efficient HER electrocatalyst.