Characterization of LiF-doped TiO2 and its photocatalytic activity for decomposition of trichloromethane

LiF-doped TiO2 was prepared by hydrolysis of tetrabutyl titanate in a mixed LiF–H2O–alcohol solution. The prepared LiF-doped TiO2 powders were characterized by X-ray diffraction (XRD), differential thermal analysis-thermogravimetry (DTA-TG), X-ray photoelectron spectroscopy (XPS), UV–vis absorption spectroscopy and photoluminescence spectra (PL). The photocatalytic activity was evaluated by the decomposition of trichloromethane (CHCl3). The results showed that LiF-doping increased the amount of OOH and oxygen vacancy (OV) on the surface of TiO2, which were beneficial to photocatalytic activity. LiF-doping inducted the new isolated energy band located above the valence band of TiO2, which extended the absorption region of TiO2 to visible light. The results of photocatalytic reaction showed that the photocatalytic activity of LiF-doped TiO2 was 2.5 times higher than that of pure TiO2.