Visible-light-driven photocatalysis on fluorine-doped TiO2 powders by the creation of surface oxygen vacancies

F-doped TiO2 (FT) powders were prepared by spray pyrolysis from an aqueous solution of H2TiF6. These FT powders demonstrated very high visible-light (Vis) photocatalytic activities for decompositions of both acetaldehyde and trichloroethylene, although their UV-Vis spectra indicated that F-doping had less effect on the optical absorption property of bulk TiO2. However, photoluminescence (PL) spectra revealed that two kinds of oxygen vacancies (F and F+ centers) were formed by F-doping. The appearance of Vis photocatalytic activity for FT powders was ascribed to the creation of these oxygen vacancies.