Electrocatalytic Performance of 2D Monolayer WSeTe Janus Transition Metal Dichalcogenide for Highly Efficient H2 Evolution Reaction

Abstract: Now-a-days, the development of clean and green energy sources is the prior interest of research due to increasing global energy demand and extensive usage of fossil fuels that create pollutants. Hydrogen has the highest energy density by weight among all chemical fuels. For the commercial-scale production of hydrogen, water electrolysis is the best method which in turn requires an efficient, cost-effective and earth-abundant electrocatalyst. Recent studies have shown that the 2D Janus TMDs are highly effective in the electrocatalytic activity for HER. Herein we report a 2D monolayer WSeTe Janus TMD electrocatalyst for HER. We studied the electronic properties of 2D monolayer WSeTe Janus TMD using periodic DFT calculations, and the direct electronic band gap was obtained to be 2.39 eV. After the calculations of electronic properties, we explored the HER intermediates including various transition state structures (Volmer TS, Heyrovsky TS, and Tafel TS) using a molecular cluster model of WSeTe noted as W10Se9Te12. The present calculations revealed that the 2D monolayer WSeTe Janus TMD is a potential electrocatalyst for HER. It has the lowest energy barriers for all the TSs among other TMDs, such as MoS2, Mn-MoS2, MoSSe, etc. The calculated Heyrovsky energy barrier (= 8.72 kcal.mol-1) for the Volmer-Heyrovsky mechanism is larger than the Tafel energy barrier (=3.27 kcal.mol-1) in the Volmer-Tafel mechanism. Hence our present study suggests that the formation of H2 is energetically more favorable via the Vomer-Tafel mechanism. This work helps shed light on the rational design of effective HER catalysts.