The effect of surface vacancy on adsorption of HS on smithsonite (101) surface: A DFT study

In this paper, the effect of Zn-vacancy defect on adsorption of HS on smithsonite (101) surface was studied by density-functional theory (DFT). The results showed that Zn-vacancy defect made the peaks of the VB and VT defect surfaces both move to left, and the peaks of them around the Fermi energy both decreased. Hence, the reactivity of VB and VT defect surfaces were both lower than that of the perfect smithsonite surface. The presence of Zn-vacancy on the smithsonite surface not only inhibited the adsorption of HS on the site of Zn-vacancy (VT-V and VB-V) but also depressed its adsorption on the Zn site nearby the Zn-vacancy (VT-BZn and VB-TZn). When HS was on the VT-BZn site on the smithsonite surface, the adsorption site of HS was the bridge between S atom the two Zn atoms, and when on the VT-V and VB-TZn sites, the adsorption site of HS was the Zn atom on the smithsonite surface. While on the VB-V site, the adsorption site of HS was the C atom on the smithsonite surface, and the bonding of S-C was formed. Meanwhile, electron transfers among the bonding atoms on smithsonite surface were observed. The results can provide insights into the sulphidization of smithsonite containing defects.