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Volume 93 Issue 1, Pages 25 – 27 |
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Guangxiu Cao, Yaogang Li, Qinghong Zhang, Hongzhi Wang |
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ABSTRACT 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. |