Density functional theory study of Ba²⁺ adsorption on KDP (100) surface

Abstract

In order to study the nature of interaction between Ba2+ and the KDP crystal surface, the adsorption behavior of Ba2+ on the KDP (100) surface was calculated by using density functional theory (DFT). The results show that the adsorption energies of Ba2+ on the KDP (100) surface are negative, indicating the adsorption processes are spontaneous and exothermic. Three types of adsorption configurations are formed after structure optimizations, and final adsorption positions are top sites on O atoms or bridge sites between two O atoms. The most stable adsorption system can be observed when Ba2+ on the bridge site between two O atoms within a phosphate group. In the three different adsorption configurations, Ba2+ can form ionic bonds with the surface O atoms, while interactions between Ba2+ and the surface H atoms exhibit covalent character. The P-O, H-O, and K-O bonds on the KDP (100) surface are elongated or shortened after Ba2+ adsorption, and the structure of hydrogen bonds on the surface also have been changed significantly.

Keywords

• dft
• adsorption
• kdp crystal
• ba²⁺