Energetics and Lateral Effects of CH2ClF Adsorbed on Anatase TiO2 (101) Surface

The adsorbate–substrate interaction between chlorofluoromethane and anatase TiO2 (101) surface has been simulated at DFT/B3LYP level, according to a previous obtained structure involving an acid–base interaction between the Cl atom and one 5-fold coordinated Ti ion and an H-bond between one H atom and one 2-fold coordinated O ion. The adsorption has been investigated considering different periodicities and surface coverages, and the energetics have been analyzed according to a recent procedure taking into account the binding, interaction, and distortion energies. The procedure allows both to quantify the direct and surface-mediated lateral effects due to the interactions between the adsorbed molecules and to determine the energies in the limit of an isolated adsorbed molecule. The obtained results suggest variations in the influence of the surface-mediated and direct lateral effects and a different behavior of the direct ones along the two directions defining the slab. The direct attraction of adsorbed molecules along the b direction leads to binding energies stronger than that referring to the limit of low surface coverage while the direct repulsion along the a direction results in a weaker adsorption. This work, allowing insights about the adsorption of CH2ClF on TiO2, shows clearly how the final binding energy of a generic compound can be affected by the interactions between neighboring molecules.