【作者】 宋宁宁；

【导师】 谭欣；

【作者基本信息】 天津大学 ， 化学工程， 2009， 硕士

【摘要】 TiO₂作为一种高效、节能、无二次污染、低成本的光催化剂,已经广泛应用于环保、制氢及能源领域。TiO₂虽然具有独特的光学性能,但是由于其禁带宽度较大（3.2eV）,只能捕获不到3%的太阳光能量（波长小于387nm）,而且光生电子-空穴对在TiO₂表面或体内能够很快复合,致使TiO₂许多应用都受到限制。因此,如何通过改性提高TiO₂在太阳光照射下的光催化效率成为目前研究的重点。本研究制备了氮掺杂改性、氮铈共掺改性纳米TiO₂光催化剂,通过比较TiO₂改性前后的光催化活性、晶体结构和化学状态特征,论述了氮掺杂、氮铈共掺杂TiO₂的光催化活性改性机理。本研究采用溶胶-凝胶法制备氮掺杂、氮铈共掺改性纳米TiO₂粉末,通过实验对比其光催化活性,使用TEM、XPS、XRD、BET、DRS等表征分析催化剂形貌、结构,通过在不同波长光照射下光催化氧化KI实验考察改性前后的光催化效率。在紫外光和可见光照射下均有如下实验结论:氮掺量为0.97 at.%的氮掺杂改性TiO₂,铈掺量为0.70 at.%,氮掺量为0.33 at.%的氮铈共掺改性TiO₂光催化活性最高。氮掺量及氮在TiO₂晶体中存在状态是影响氮掺杂和氮铈共掺改性TiO₂光催化活性的主要因素,变价铈离子对光催化剂的的特殊作用也是影响氮铈共掺改性纳米TiO₂的因素。更多还原

【Abstract】 Titanium dioxide exhibits unique photo-functionalities that make it an excellent choice for photocatalytic applications in environmental protection, hydrogen production and energy fields due to TiO₂ is a highly effective, saving energy, without any further polluted and low cost photocatalyst. However many applications have been limited by its large band gap （3.2eV） which can only capture less than 3% of the solar irradiance （wavelength < 387nm）, and the fast recombination of photogenerated electron-hole pairs both on the surface and in the lattice of TiO₂. So, the current issue is how to improve its efficiency under sunlight irradiation by structure modification.The modified TiO₂ photocatalyst doped with nitrogen and/or cerium were synthesized in this paper. By comparing their photocatalytic activity, crystal structure and chemical state characterization, the mechanism of doped nitrogen and/or cerium elements on photocatalytic activity of nitrogen and/or cerium doped TiO₂ have been discussed.The nitrogen with/without cerium co-doped TiO₂ nanoparticles were synthesized via Sol-gel technique. Photocatalysts were characterized by TEM, XPS, XRD, BET, and DRS. By the KI photocatalytic oxidation experiments under different wavelengths irradiation were carried out and their catalytic efficiency were studied. From the current results we could concluded: the optimal doped ratio is 0.97 at.% nitrogen for nitrogen doped TiO₂, and 0.70 at.% cerium and 0.33 at.% nitrogen for nitrogen and cerium co-doped TiO₂. Doping nitrogen and its chemical state in TiO₂ nanocrystal are the important impact factors on the photocatalytic activity of nitrogen with/without cerium co-doped TiO₂ nanoparticles. The special role of cerium as a variable valence element is another factor on the photocatalytic activity of nitrogen and cerium co-doped TiO₂.更多还原