A study of two-dimensional single atom-supported MXenes as hydrogen evolution reaction catalysts using density functional theory and machine learning

Screening promising hydrogen evolution reaction (HER) electrocatalysts for water splitting is crucial for the industrial scalability of sustainable energy storage. As HER catalysts, two-dimensional (2D) MXenes are promising substitution materials for platinum. Tuning the surface termination and loading a single atom can help to improve the electrocatalytic performance of 2D MXenes. We utilized density functional theory (DFT) calculations to explore the catalyst activity, thermal stability, and dynamic stability of 2D single atom-loaded MXenes with surface terminations. We demonstrate that 21 uninvestigated 2D single-atom MXene catalysts, among 264 promising candidates, show an electrocatalytic activity surpassing that of platinum. Among the 21 most promising HER catalysts, 7 (Ti3C2I2-Ir, Ti3C2Br2-Cu, Ti3C2Br2-Pt, Ti3C2Cl2-Cu, Ti3C2Cl2-Pt, Ti3C2Se2-Au, and Ti3C2Te2-Nb) are dynamically and thermally stable. Furthermore, machine learning tools predicted the catalyst activity and thermal stability using elemental properties that are easily available in chemical data repositories.