Stability and electronic properties of hydrogenated MoS₂ monolayer: A first-principles study

First-principles total energy studies are used to investigate the stability of hydrogenated MoS₂ monolayer (MoS₂-H_x) (x = 1-8), which is a compound with different numbers of H atoms adsorbed on the MoS₂ surface. Energetically, the S-top side of the MoS₂ is found to be the most favorable for H-adsorption. H₂S and graphene are well-known to be stable, and MoS₂-H_x is predicted to be even more stable because its binding energy is lower than that of H₂S and its formation energy and adsorption energy are lower than those of graphene. The analysis of the electronic density distribution and the orbital hybrid also shows that MoS₂-H_x forms stable structures. In addition, the influence of the number of the adsorbed H-atoms in the MoS₂-H_x on the electronic structure of the compound is also investigated. The MoS₂-H_x band structure exhibits a dispersion and the MoS₂-H_x band gap gradually decreases from 1.72 eV to 0 eV as the number of adsorbed H atoms increases. The corresponding work function increases as a result of the strengthening of the dipole moment formed between the H atoms that are adsorbed and the hydrogenated MoS₂.