Structural, electronic and magnetic properties of the Ni/Cu-embedded S-vacancy defective MoS_2 monolayers and their effects on the adsorption of SO_x and O_3 molecules

摘要

By using density functional theory (DFT) calculations, we predicted the structural, electronic and magnetic properties of S-vacancy defective MoS2 monolayers upon embedding Cu and Ni atoms. Firstly, we computed the binding energies for Cu and Ni embedding to the defective MoS2 structure and found that Ni embedding gives rise to the more stable structure compared to the Cu embedding. Then, we systematically inspected the adsorption of O-3, SO2 and SO3 gas molecules on their surfaces. It was found that Cu/Ni embedding significantly improves the interaction of gas molecules with MoS2 monolayers. Band structure calculations indicate that Cudoped MoS2 system exhibits metallic behavior, while Ni-MoS2 system reveals semiconductive nature. Besides, the Cu-MoS2 system shows a total magnetic moment of 1.0 mu B, which indicates the magnetic property induced by Cu embedding in the structure. Thus, Cu/Ni embedding is conductive to the adsorption of gas molecules on the MoS2 nanosheets. All the gas molecules were strongly chemisorbed on the Cu site of Cu-MoS2 systems. An increase of charge density between the interacting atoms indicate the formation of chemical bonds at the interface area.