Abstract: The lanthanide ions-doped TiO2 samples with different content were prepared by the sol-gel method using titanium tetrachloride and lanthanide chloride as the raw materials. The samples were characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PLS), surface photovoltage spectroscopy (SPS), and X-ray photoelectron spectroscopy (XPS). The XRD result indicated that the lanthanide ions did not enter the crystal lattices of TiO2. The intensity of PLS and SPS related to the surface oxygen vacancies and defects as well as the separation and recombination of photoinduced charge carriers changed with the kinds of lanthanide ions and the dopant content. The photocatalytic activity of the samples for the degradation of aqueous imidazole was tested under UV light. The result showed that the appropriate content of lanthanide dopants could effectively promote the separation effect of surface photoinduced charge carriers on TiO2, which was responsible for the remarkable increase in photocatalytic activity.

Key words: lanthanide ion, titania, sol-gel method, imidazole, photocatalysis, degradation