Catalytic Activity of MS2 Monolayer for Electrochemical Hydrogen Evolution

Abstract

Finding earth-abundant and inexpensive materials to catalyze the electrochemical hydrogen evolution reaction (HER) is critical for turning hydrogen into a competitive clean energy source. Breakthrough discoveries of high activity toward HER have been reported using two-dimensional transition metal dichalcogenides. Here, we performed a comprehensive investigation on the three most common MS2 single-layer materials, with M being Mo, W, V, and with ab initio calculations to lay a theoretical framework on the dynamic stability and HER activity of the common polymorphs (1H, 1T, and ZT phases) of these MS2 monolayers. First, our calculations show that the HER catalytic activity of these MS2 monolayers generally reduces with the increase of hydrogen coverage, except that, although the HER performance of 1T-VS2 is indeed best at low hydrogen coverage, the HER performance of 1H-VS2 is best when the coverage is large. In addition to the effects of hydrogen coverage, we show that the HER activity of WS2 can be impro...