Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (04): 939-945.doi: 10.3866/PKU.WHXB20110401

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Visible-Light-Driven Catalytic Properties and First-Principles Study of Fluorine-Doped TiO2 Nanotubes

SU Ya-Ling1,2, LI Yi3, DU Ying-Xun1, LEI Le-Cheng2   

  1. 1. Nanjing Institute of Geography & Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008, P. R. China;
    2. Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310028, P. R. China;
    3. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, College of Environmental Science and Engineering, Hohai University, Nanjing 210098, P. R. China
  • Received:2010-11-01 Revised:2011-01-20 Published:2011-03-29
  • Contact: SU Ya-Ling, LEI Le-Cheng E-mail:lclei@zju.edu.cn; ylsu@niglas.ac.cn
  • Supported by:

    The project was supported by the Fund of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, China (2009490911) and National Natural Science Foundation for Young Scientists of China (20906097).

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Abstract:

Improving the photocatalytic activity and the utilization of visible light of TiO2 is the most important research topics in the photocatalytic field. To improve the photocatalytic activity of TiO2, we used chemical vapor deposition (CVD) to dope TiO2 nanotubes with fluorine. Scanning electron microscopy (SEM) images showed that the annealing temperature significantly affected the morphological integrity of TiO2 nanotubes. Upon annealing at 550 and 700 °C, the structure of F-doped TiO2 nanotubes suffered from an observable disintegration of morphological integrity. X-ray diffraction (XRD) results indicated that the F impurity retarded the anatase-rutile phase transition. Fluorine was successfully doped into TiO2 by CVD, as indicated by the X-ray photoelectron spectroscopy (XPS) results. F-doped TiO2 nanotubes showed higher photocatalytic activity. First-principles calculations suggested that the F 2p states were located in the lower-energy range of valence band (VB) and less mixed with O 2p states. It thus contributed little to the reduction of the optical band gap. This is consistent with the finding that the band gap of F-doped TiO2 is very close to that of undoped TiO2. Therefore, the higher catalytic activity of F-doped TiO2 should be attributed to the creation of surface oxygen vacancies upon F-doping, which enhances surface acidity and increases the amount of Ti3+ ions.

Key words: TiO2 nanotubes, Fluorine-doping, Visible-light, Catalytic property, Electronic structure