Photocatalytic degradation of organic compounds on TiO2 powders - FT-IR investigation of surface reactivity and mechanistic aspects

This review examines a series of studies investigating the molecular phenomena occurring on the surface of TiO2, in the dark and under ultra violet spectroscopy (UV) irradiation, in processes intended to achieve the photocatalytic abatement of organic pollutants (e.g. phenols, VOCs, acetonitrile) of air and water. The investigation technique was fourier transform infrared spectroscopy (FT-IR), applied under simulated operating conditions, augmented with high resolution transmission electron microscopy for the elucidation of the surface structure and morphology of the TiO2 particles. The results indicate the key role of surface hydroxyl groups as adsorbing/reacting centres (under UV irradiation) and the possibility that basic surface centres (hydroxyl groups and/or surface O2- of the TiO2 lattice) also affect the surface chemical processes.