Density functional theory was used to investigate the adsorption, diffusion, and dissociation of H2O on kaolinite(001) surface. It was found that the preferred adsorption sites on the kaolinite(001) surface for H2O were the threefold hollow sites with the adsorption energies ranging from 1.06 to 1.15eV. H2O does not adsorb on the six-fold hollow site of the aluminium(001) face of the third layer of kaolinite, implying that it was difficult for water molecules to penetrate the ideal kaolinite(001) surface. In addition, calculations were made of the energetic barriers to the diffusion of H2O between the most stable and next most stable adsorption sites, which ranged from 0.073 to 0.129eV. The results also showed that H2O molecules were easy to diffuse on the kaolinite(001) surface. Finally, the study indicated that no dissociation state exists for the H2O on kaolinite(001) surface.

Adsorption, Diffusion, and Dissociation of H2O on Kaolinite (001) - a Density Functional Study. M.C.He, J.Zhao: Chinese Physics Letters, 2012, 29[3], 036801