Abstract: LiF-doped TiO2 catalysts were prepared by the sol-gel method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and photoluminescence. The photocatalyst activity for the degradation of methylene blue was evaluated, and the effects of the LiF doping amount, annealing temperature, and pH value of the reaction liquid were investigated. LiF doping favored the formation of the rutile phase, introduced a large amount of hydroxyl, and increased the oxygen vacancy concentration on the surface of TiO2, which led to the high photocatalytic activity of LiF-doped TiO2. Under the conditions of 8% LiF doping, annealing temperature of 500 ℃, and reaction liquid pH value of 6.6, the photocatalytic activity of LiF-doped TiO2 was 5 times higher than that of undoped TiO2.

Key words: sol-gel method, titania, lithium fluoride, doping, methylene blue, photocatalytic degradation