Structural and Electronic Properties of Monolayer 1T-MoS2 Phase, and Its Interaction with Water Adsorbed on Perfect, Single S-Vacated and MoS2-Unit-Vacated Surface: Density Functional Theory Calculations

Using density functional theory calculations with van der Waals dispersion corrections, we studied the structural and electronic properties of monolayer 1T-MoS2, and how it interacts with water on perfect and vacancy-doped cases, which include single sulfur and MoS2-unit vacancies. We first optimized and calculated its structural parameters and electronic properties and confirmed earlier reports suggesting its metastable state and metallic electronic structure. Results show that adsorption sites on perfect surface bind water weakly while the opposite is true for vacancy sites adsorption. Climbing nudged elastic band calculations revealed that sulfur vacancy site could favorably dissociate water and evolve hydrogen with moderate energy cost, while significantly high energies are required for the same processes on MoS2 unit vacancy. The results are important in supplementing efforts to find clean and renewable energy sources.