Ab Initio Simulations of the Interaction between Water and Defects on the Calcite (101̅ 4) Surface

Autor: Lardge, Jennifer S., Duffy, Dorothy M., Gillan, Mike J., Watkins, Matthew
Zdroj: The Journal of Physical Chemistry - Part C; February 2010, Vol. 114 Issue: 6 p2664-2668, 5p
Abstrakt: The interaction between water and calcite surfaces is relevant to a broad range of technological processes, but a fundamental understanding of the nature of the adsorbed water is still lacking. In an earlier publication we used density functional theory calculations to calculate the interaction between water and perfect (101̅ 4) calcite surfaces. Water was found to be strongly adsorbed as associated molecules. In this paper water adsorption on (101̅ 4) calcite surfaces with steps and vacancies is investigated. A water molecule was found to bind more strongly to acute steps than to obtuse steps. The lowest energy position was found to be the base of the step for acute steps and on top of the step for obtuse steps. Water molecules were found to exhibit very strong binding to surface vacancies. Associative adsorption was favored near cation vacancies; however, the water was found to dissociate, to form a bicarbonate ion and a hydroxide ion, near anion vacancies.
Databáze: Supplemental Index