Unveiling electronic constraints on basal planes of 2D transition metal chalcogenides for optimizing hydrogen evolution catalysis: A theoretical analysis

Two-dimensional transition metal dichalcogenides (2D-TMDs) have emerged as promising alternatives to noble metal platinum for hydrogen evolution reaction (HER) electrocatalysts. However, their inert basal planes present a significant challenge, and effective activation strategies have not been fully explored. In this study, we address this gap by performing density functional theory (DFT)-based first-principles calculations to develop a comprehensive theoretical framework for activating the basal planes of 2D-TMDs. We reveal two key electronic descriptors—(1) the energy of the lowest unoccupied state (E_lu) and (2) the degree of valence electron localization—that govern hydrogen adsorption on the basal planes. These insights form the foundation of a novel strategy: precision doping of metal atoms onto the basal planes of Mo- and W-based 2D-TMDs. This strategy provides unprecedented control over the electronic structures at the active sites, significantly enhancing valence electron localization and improving HER activity. Additionally, we determine the optimal doping concentration, offering crucial guidance for experimental studies. Our work presents a pioneering, descriptor-driven methodology for activating 2D-TMD basal planes, providing transformative insights for HER electrocatalyst design. This research sets a new direction for developing highly efficient water-splitting technologies, accelerating progress toward sustainable hydrogen production.