Adsorption mechanism of hydrogen sulfide and sulfur dioxide on Au-MoS2 monolayer

Based on density functional theory (DFT) theoretical calculations, Au-MoS2 monolayer was used as the adsorbent to remove the typical decomposition components (H2S and SO2) generating in SF6-insulated equipment. The adsorption structure, adsorption energy, charge transfer, HOMO, LUMO, and the density of states (DOS) of single and double H2S and SO2 molecules adsorption on Au-MoS2 monolayer were analyzed. It is found that Au atom acts as the active site for gas adsorption, and the gas molecules tend to adsorb on Au-MoS2 monolayer surface at Au doping site by building a chemical bond with Au atom. H2S adsorption makes the conductivity of the adsorption system increase. On the contrary, SO2 adsorption leads to the decrease of adsorption system. Due to the strong repulsive force between gas molecules, Au-MoS2 monolayer only shows strong interaction to one of the gas molecule during the double gas molecules adsorption process. The adsorption energy of single and double H2S adsorption are -0.96 eV, -1.35 eV, and single and double SO2 adsorption are -1.18 eV and -1.44 eV. In conclusion, Au-MoS 2 monolayer shows optimal adsorption ability to H2S and SO2, which makes it potential adsorbent material using in SF6-insulated equipment.