Theoretical Study of MoS₂ Defects and Dopants for Hydrogen Evolution Reaction

Hydrogen is one of the predominant, clean and renewable alternatives to fossil fuels. Efficient and sustainable hydrogen production is key to its widespread use as an energy carrier in the near future. Molybdenum disulfide (MoS₂) is an earth-abundant, low cost, layered material with a variety of interesting properties, which depend on its dimensionality and structure. Density Functional Theory (DFT) calculations were performed to examine the hydrogen adsorption ability of MoS₂ basal plane when modified by defects and dopants. Introduction of a sulfur vacancy in combination with a nearby Mo-atom substitution by a transition metal enhances basal plane activity. Parameters such as hydrogen adsorption free energy (ΔG_H), adsorption sites, hydrogen coverage, desorption mechanisms and stability are examined. Our findings suggest that the combination of a single Ni atom dopant and a sulfur vacancy formation in the MoS₂ basal plane has the maximum performance compared to several other metal dopants. The examination of other transition metal doped configurations sets the guidelines for designing efficient and stable MoS₂-based catalysts for HER.