A non-metal doped VTe₂ monolayer: theoretical insights into the enhanced mechanism for the hydrogen evolution...

Two-dimensional transition metal dichalcogenides (TMDCs), such as vanadium ditelluride (VTe₂), have emerged as promising catalysts for the hydrogen evolution reaction (HER) due to their unique layered structures and remarkable electronic properties. However, the catalytic performance of pristine VTe₂ remains inferior to that of noble metals. In this study, density functional theory (DFT) calculations were employed to systematically investigate the influence of fourteen different non-metal dopants on the HER activity of VTe₂. Our results disclose that N-VTe₂, P-VTe₂ and As-VTe₂ possess exceptional catalytic properties for the HER with the Gibbs free energy of hydrogen adsorption (ΔG_H*) values of 0.031, -0.032 and 0.024 eV, respectively. Furthermore, analyses of the geometric and electronic structures reveal that non-metal doping induces localized geometric distortions and charge redistribution, thereby altering the electronic environment of active sites and enhancing catalytic performance. More importantly, a composite descriptor φ, integrating the bond length between doped non-metal atoms and neighboring V atoms (L_NM-M) and the pz band center (ε_pz) of the doped atoms, demonstrates a strong correlation with ΔG_H* and may serve as an effective predictor of HER activity. These findings shed light on non-metal doping as an effective strategy for developing efficient, non-noble metal HER catalysts based on TMDCs.