Title : Multilevel engineering of VSe₂ for efficient multifunctional electrocatalysis: A DFT-guided approach
Abstract:
Hydrogen is considered a promising clean and renewable energy carrier for addressing the growing demand for sustainable energy conversion and storage. However, the efficiency and economic viability of hydrogen-related technologies strongly depend on the development of highly active, stable, and cost-effective electrocatalysts for key reactions including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). Although noble-metal-based catalysts exhibit excellent catalytic performance, their high cost and limited availability have stimulated extensive research into earth-abundant alternatives. Transition-metal dichalcogenides (TMDs), particularly vanadium diselenide (VSe?), offer attractive opportunities because of their layered structure and tunable electronic properties. In the present study, the electrocatalytic performance of monolayer VSe? was systematically investigated using density functional theory (DFT), with the aim of developing multifunctional catalysts through structural and electronic-structure engineering.
The effects of intrinsic defects, including Se and V vacancies and V–Se double vacancies, were first explored. Selected defect structures exhibited near-optimal HER activity, with ΔGH* values of 0.04–0.06 eV, while the D2 configuration showed favorable OER and ORR overpotentials of 0.19 and 0.46 V, respectively. Subsequently, transition-metal (TM) and non-metal (NM) doping were employed to further tailor the catalytic properties. Several doped systems exhibited near-thermoneutral hydrogen adsorption, with Cu@D2 achieving ΔGH* = 0.09 eV and OER/ORR overpotentials of 0.49/0.38 V. Finally, electric-field and strain engineering provided additional control over catalytic activity, with +2% tensile strain tuning Cu@D2 and Zn@D2 to ΔGH* values of 0.02 and −0.02 eV, respectively.
These results demonstrate that defect, elemental-doping, and external-field engineering can be strategically combined to optimize the electronic structure and catalytic activity of VSe?, highlighting its potential as a non-noble-metal platform for multifunctional electrocatalysis and sustainable hydrogen-energy applications.
