Enhancing hydrogen evolution reaction performance through defect engineering in WTeX (X= S, Se) monolayers: A first-principles study

Abstract

Finding a novel material to substitute the existing noble metal catalysts for the hydrogen evolution reaction (HER) is essential for the further advancement of water electrolysis technology. Herein, we investigated the feasibility of using defect engineering to improve the hydrogen evolution reaction (HER) catalytic performance of WTeX (X = Se, S) materials in the 2H, 1 T, and 1 T′ phases. The results demonstrate that the introduction of defects significantly enhances WTeX monolayers’ HER performance. As exemplary cases, the Gibbs free energy changes for 2H WTeSe with a Te vacancy (2H WTeSe–VTe) and 2H WTeS with a Te vacancy (2H WTeS–VTe) are 0.029 eV and −0.002 eV, respectively. It was found that the active sites in 2H WTeSe–VTe and 2H WTeS–VTe have a substantial number of empty anti-bonding states, which increases the bond strength between H and the catalyst, leading to exceptional catalytic performance. This work demonstrates the feasibility of defect-engineered WTeX structures as electrocatalysts and provides a reliable reference for the study of non-precious metal catalysts.