Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (06): 1305-1312.doi: 10.3866/PKU.WHXB201303182

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Structure, Characterization and Photocatalytic Properties of TiO2 Doped with Different Content of Sn4+ Ions

ZHANG Peng1,2, ZHAO Lu Song1,2, YAO Jiang Hong1,2, CAO Ya An1,2   

  1. 1 College of Physics, Nankai University, Tianjin 300071, P. R. China;
    2 Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, Teda Applied Physics School, Nankai University, Tianjin 300457, P. R. China
  • Received:2012-12-11 Revised:2013-03-18 Published:2013-05-17
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51072082, 21173121, 11074129) and National Key Basic Research Program of China (973) (2012CB934201).

Abstract:

Pure TiO2 and Sn4+ doped TiO2 (TiO2-Snx%) photocatalysts were prepared by a sol-gel method, where x% represents the nominal molar fraction of Sn4+ ions in the Zr4+ structure. The crystal structure and energy band structure of the resultant catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface photovoltage spectroscopy (SPS).The results show that for a low content of Sn4+ ions, the Sn4+ ions are doped into the TiO2 lattice and replace lattice Ti4+ ions in a substitute mode (Ti1-xSnxO2). The energy levels of these Sn4+ ions are located 0.38 eV below the conduction band. Moreover, the rutile SnO2 crystal structure evolves with increasing content of Sn4+ ions, i.e., a TiO2/SnO2 structure is formed. The conduction band of SnO2 is located 0.33 eV lower than that of TiO2. The separation and recombination mechanism of the photo-generated carriers was characterized by photoluminescence and transient photovoltage techniques. The results showed that the formation of the energy levels of Sn4+ ions and the conduction band of rutile SnO2 can enhance the separation of the photogenerated carriers, and suppress the recombination of photo-generated carriers. However, the energy levels of Sn4+ can lead to a much longer life time and higher separation efficiency of the photo-generated carriers. For different content of Sn4+ in Sn4+ ion doped TiO2(TiO2-Snx%), the abovementioned aspects improve the photocatalytic activity.

Key words: Sn4+-doped TiO2, Content of Sn4+ ions, Transient photovoltage, Surface photovoltage spectroscopy, Life time of photo-generated electrons

MSC2000: 

  • O648