Abstract: The pure and Sm-doped TiO2 nanopowders were prepared by sol-gel method. The samples were characterized by XRD, XPS, FT-IR, UV-Vis, PL and Nano-sizer nano particle size analyzer, etc. The effects of Sm-doping on structure and visible photocatalytic properties of TiO2 photocatalyst was evaluated by photocatalytic degradation of methylene blue ( MB ) under the irradiation of fluorescent lamp. The results show that samarium appeared two kinds of Sm3+ and Sm2+ valence state on the surface of TiO2 . Samarium doping can restrain the phase transfer from anatase to rutile, prevent the grain growth, and increase the surface hydroxyl content. Appropriate doping amount of Sm can broaden TiO2 's, spectrum absorption region to visible light and effectively inhibit the recombination of photoelectron-hole pairs. Meanwhile, the photocatalytic activity of the 1. 0wt;Sm-doped TiO2 samples calcined at 500 ℃ is the better under the irradiation of fluorescent light, it is 97; within 6 h and significantly higher than 56; of P25 produced by Degussa under the same experimental conditions.

Key words: The pure and Sm-doped TiO2 nanopowders were prepared by sol-gel method. The samples were characterized by XRD, XPS, FT-IR, UV-Vis, PL and Nano-sizer nano particle size analyzer, etc. The effects of Sm-doping on structure and visible photocatalytic properties of TiO2 photocatalyst was evaluated by photocatalytic degradation of methylene blue ( MB ) under the irradiation of fluorescent lamp. The results show that samarium appeared two kinds of Sm3+ and Sm2+ valence state on the surface of TiO2 . Samarium doping can restrain the phase transfer from anatase to rutile, prevent the grain growth, and increase the surface hydroxyl content. Appropriate doping amount of Sm can broaden TiO2 's, spectrum absorption region to visible light and effectively inhibit the recombination of photoelectron-hole pairs. Meanwhile, the photocatalytic activity of the 1. 0wt;Sm-doped TiO2 samples calcined at 500 ℃ is the better under the irradiation of fluorescent light, it is 97; within 6 h and significantly higher than 56; of P25 produced by Degussa under the same experimental conditions.