物理化学学报 >> 2013, Vol. 29 >> Issue (06): 1305-1312.doi: 10.3866/PKU.WHXB201303182

催化和表面科学 上一篇    下一篇

不同浓度Sn4+离子掺杂TiO2的结构、性质和光催化活性

张鹏1,2, 赵路松1,2, 姚江宏1,2, 曹亚安1,2   

  1. 1 南开大学物理科学学院, 天津 300071;
    2 南开大学泰达应用物理学院, 弱光非线性光子学教育部重点实验室, 天津 300457
  • 收稿日期:2012-12-11 修回日期:2013-03-18 发布日期:2013-05-17
  • 通讯作者: 曹亚安 E-mail:caoyaan@yahoo.com
  • 基金资助:

    国家自然科学基金(51072082, 21173121, 11074129)和国家重点基础研究发展规划项目(973) (2012CB934201)资助

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).

摘要:

采用溶胶-凝胶法制备出纯TiO2和不同浓度Sn4+离子掺杂的TiO2光催化剂(TiO2-Snx%, x%代表Sn4+离子掺杂的TiO2样品中Sn4+离子摩尔分数). 利用X 射线衍射(XRD)、X 射线光电子能谱(XPS)和表面光电压谱(SPS)确定了TiO2-Snx%催化剂的晶相结构和能带结构, 结果表明: 当Sn4+离子浓度较低时, Sn4+离子进入TiO2晶格, 取代并占据Ti4+离子的位置, 形成取代式掺杂结构(Ti1-xSnxO2), 其掺杂能级在导带下0.38 eV处; 当Sn4+离子浓度较高时, 掺入的Sn4+离子在TiO2表面生成金红石SnO2, 形成TiO2和SnO2复合结构(TiO2/SnO2), SnO2的导带位于TiO2导带下0.33 eV处. 利用瞬态光电压谱和荧光光谱研究了TiO2-Snx%催化剂光生载流子的分离和复合的动力学过程, 结果表明, Sn4+离子掺杂能级和表面SnO2能带存在促进光生载流子的分离, 有效地抑制了光生电子与空穴的复合; 然而, Sn4+离子掺杂能级能更有效地增加光生电子的分离寿命, 提高了光生载流子的分离效率, 从而揭示了TiO2-Snx%催化剂的光催化机理.

关键词: Sn4+离子掺杂TiO2, Sn4+离子浓度, 瞬态光电压, 表面光电压谱, 光生电子的寿命

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