Effects of defects and impurities on the adsorption of H2O on smithsonite (101) surfaces: Insight from DFT-D and MD

Abstract

In this paper, DFT-D calculations and MD simulations were first performed to systematically study the H 2 O adsorption on smithsonite (101) surface with different defects and impurities, mainly including Zn-vacancy defect and Fe, Mn, Cd, Co impurities. We found the H 2 O adsorption on the defective and impurity smithsonite surfaces were all depressed compared with the perfect surface. Moreover, we found the adsorption forms of H 2 O also changed greatly. The single H 2 O on perfect surface was dissociated adsorption, which mainly included the hybridizations of Zn 3d with O 2p orbitals as well as H 1s with O 2p orbitals, while that on Zn-vacancy surfaces changed to molecular adsorption, which mainly included the hybridization between Zn 3d and O 2p orbitals, and that on impurity surfaces can be observed both molecular and dissociated adsorption, which mainly included the hybridizations of d orbital of impurity atoms with O 2p orbital as well as H 1s with O 2p orbitals for the dissociated adsorption while d orbital of impurity atoms with O 2p orbital for the molecular adsorption. The analysis results demonstrated that the adsorption of H 2 O on the perfect smithsonite (101) surface was stronger and more stable than that on the defective and impurity surfaces. The adsorption of H 2 O on defective and impurity smithsonite surfaces was all depressed than the perfect surface.