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Enhanced Visible Light-Driven Photocatalytic Performance of La-Doped TiO2−xFx


  • H.-W. Wang—contributing editor

  • This work was supported by Cultivation Fund of the Key Scientific & Technical Innovation Project (no. 708039), National Natural Science Foundation of China (no. 50772022 and 50772127), and the National Key Technology R & D Program (no. 2006BAA04B02-01).

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La-doped TiO2−xFx (La–TiO2−xFx) powders were prepared by the sol–gel method. X-ray diffraction results showed that La efficiently inhibited grain growth. X-ray photoelectron spectroscopy spectra revealed that La2O3 and O–Ti–F bonds have formed, the La2O3 maintained the high surface area of TiO2−xFx after calcination at a temperature above 500°C, while the O–Ti–F bonds increased the oxidation potential of the photogenerated hole in the valence band. The UV-vis spectroscopy of the La–TiO2−xFx showed that the presence of intraband gap states was likely responsible for its absorption of visible light. When the molar ratios of La and F to Ti were 1.5:100 and 5:100, respectively, and calcined at 500°C, the photocatalytic degradation rate of methylene blue over La–TiO2−xFx was about 1.5 times higher than that of F-doping TiO2.