Depletion of conduction band electrons in TiO 2 by water chemisorption – IR spectroscopic studies of the independence of Ti–OH frequencies on electron concentration

Abstract

The chemisorption of water at 300 K onto reduced TiO 2 produces both adsorbed Ti–OH groups and chemisorbed water. During the adsorption of H 2O, the concentration of conduction band electrons is found to decrease as measured by transmission infrared spectroscopy. The TiO 2 electron depletion process occurs predominantly during the first stages of water adsorption, probably due to Ti–OH species formation. It is also found that the infrared spectrum of Ti–OH groups in the ν(OH) region is not influenced by the electronic state of the TiO 2 surface, comparing TiO 2 containing different concentrations of conduction band electrons.