Theoretical investigation of dissociative and non-dissociative acetic-acid on TiO2-B surfaces

Interaction between acetic acid and TiO₂-B surfaces are investigated by first-principles calculations based on density functional theory (DFT). We found non-dissociative adsorption configurations are energetic favorable. We also found that the favorable adsorption configuration is not only determined by the matched interface structures, but also by the electrostatic potential distribution on the Lewis acid (Ti*) and basic (O*) sites. Although the TiO₂-B (100) surface exhibits the highest surface energy among the all low-index clean surface, the TiO₂-B (010) surface displaces a stronger oscillation of electrostatic potential between the Lewis acid and basic sites which provides an extra driving force to promote acetic acid dissociation and leads to larger adsorption energy. Such strong oscillatory electrostatic potential provides an extra driving force to promote acetic acid dissociation, which leads to larger adsorption energy. Our results provide a detailed insight into the adsorption structure and mechanism and further shed light on the photochemistry on surface at the molecular level.