DFT+U calculations of the interaction of Cl with defect-free hydroxylated Cu_2O(100) surface

摘要

Periodic DFT+U calculations have been performed on a defect-free (100)-oriented hydroxylated Cu_2O surface to model adsorption and sub-surface insertion of Cl at the surface passive film on copper. The exchange of surface OH groups by the Cl and the insertion of Cl in the sub-surface layer have been investigated. The charge transfer between hydroxylated Cu_2O(100) surface and Cl is also calculated. The results evidence that the mixed topmost OH/CI planes are splitted induced by Cl adsorption. The substitution of surface hydroxyls by Cl is found to be endothermic with the substitution energy increasing with Cl coverage and the insertion of Cl in the first oxide layers is endothermic but with the insertion energy decreasing with Cl coverage, which are related with the repulsive electrostatic interactions between adsorbed Cl ions for increasing coverage. The relationship between charge transfer and substitution energy or insertion energy is also discussed.