Dissociation behavior of water molecules on defect-free and defective rutile TiO2 (101) surfaces

In the current investigation, reactive molecular dynamics simulation has been used to study and compare the dissociation behavior of water molecules on defect-free and defective ruffle TiO2 (1 0 1) surface. According to the contour map for a water molecule on the TiO2 (1 0 1) surface, water molecules have proven to dissociate around 20 times faster in the defective surface rather than defect-free surface. In the presence of defects, the oxygen atoms near the defects have lower electrostatic potentials and therefore higher reactivity which adsorption of molecules to the defects and their vicinity increases while for the defect-free surface, water molecules are adsorbed like clusters and exhibit lower dispersion. Also investigation of the density profile has proven water molecules have better dispersion through the defective surface. Namely, presence of defects leads water molecules to be adsorbed at different spots through the surface. In addition to the density profile, dissociation of water molecules to hydroxyl groups and respective diffusion of hydrogen atoms into the surface (down to the second sub-layer) has been undertaken through inspection of contours for water molecules in the defective surface throughout the simulations.