Relaxation Processes of Water Molecules on Surfaces of Highly Dispersed Silica and Titania/Silica

Abstract

Analyses of dielectric spectra and theoretical simulation results demonstrate that the most probable sites for water cluster adsorption are the B-sites at the TiO 2 /SiO 2 (TS) phase boundary regions and the SiOH groups on the SiO 2 phase in TS. The amount of water on SiO 2 in TS is lower than for pure SiO 2 for the same content of water at the TiO 2 /SiO 2 and SiO 2 surfaces. The energy necessary for the rotation of a water molecule is a maximum for molecules linked via one electron-donor bond M←OH 2 and three hydrogen bonds with other water molecules.