【作者】 陈喜明；

【导师】 蒋新；

【作者基本信息】 浙江大学 ， 应用化学， 2005， 硕士

【摘要】 本文主要研究掺杂SiO₂和V₂O₅对纳米TiO₂薄膜超亲水性和光敏性的影响。论文首先综述了纳米复合材料和纳米TiO₂的应用,对目前的一些纳米复合材料的制备方法进行了分类。详细阐述了TiO₂薄膜超亲水性的影响因素、亲水机理、特点和应用,并总结了提高超亲水性和光敏性的手段,最后提出了自己的研究方向和思路。 论文中以溶胶-凝胶法结合浸渍-提拉技术制备了TiO₂薄膜、SiO₂-TiO₂和V₂O₅-TiO₂复合薄膜和复合粉末,结合X射线衍射仪（XRD）,高分辨扫描电镜（HRSEM）、原子力显微镜（AFM）和热失重-差热（TG-DTA）对薄膜进行表征,建立结构与亲水性的关系。 针对不同的体系,作者通过对文献和现有分析手段的研究设计了一系列的实验。研究发现,对于SiO₂-TiO₂复合薄膜,SiO₂的加入能够抑制TiO₂锐钛矿晶型向金红石晶型的转化,并且抑制TiO₂锐钛矿型晶粒的生长。复合薄膜的亲水性跟晶粒粒径有关,在TiO₂具有一定绝对含量的条件下,晶粒越小越有利于薄膜的亲水性;对于V₂O₅-TiO₂复合薄膜,V₂O₅的引入对TiO₂晶粒大小以及晶型转化的影响类似于SiO₂的引入,都能抑制锐钛矿晶型向金红石晶型的转化,并且抑制TiO₂锐钛矿型晶粒的生长。此外更重要的是,V₂O₅的引入拓展了TiO₂薄膜的光谱响应,V₂O₅-TiO₂复合薄膜在太阳光的照射下,也能展现出良好的亲水性能,接触角从照射前的35°左右下降到8°左右,而单纯的TiO₂薄膜在太阳光的照射下,其接触角却几乎不变,随着钒添加量的增加,接触角总体上呈现下降趋势;对于光敏化机理的研究,V₂O₅-TiO₂复合薄膜具有可见光响应的特性主要是由于V₂O₅的掺杂在二氧化钛的能带中引入钒的3d能级,从而使光响应波长从紫外光向可见光的方向移动,并且由于V₂O₅是窄禁带半导体,与TiO₂宽禁带半导体相复合,也能够提高电荷分离效率,扩展TiO₂的光谱响应。 论文最后总结论文工作的同时,提出了论文没有解决的问题,为以后TiO₂薄膜亲水性和光敏化更进一步的研究工作明确了方向。更多还原

【Abstract】 The effect of doped SiO₂ and V₂O₅ on the super-hydrophilicity and sensitivity of nano TiO₂ thin films were studied in this dissertation. First, the research and application of nanocompsites and nano TiO₂ were reviewed and the author introduced the preparation methods of nanocomposites in response to the dissertation. The author generalized the effect factor principles, characteristics and applications of the thin film. And several kinds of methods of improving the super-hydrophilicity and sensitivity were represented detailed. And at last, on base of it the investigated orientation of this dissertation was presented.In this research, TiO₂ thin film, SiO₂-TiO₂ and V₂O₅-TiO₂ nanocomposite thin films and nanocomposite powder were prepared on glass substrates by sol-gel processing and dip-coating technique. The films as well as the dried powder of bulk gel were characterized by different techniques, such as X-ray diffraction （XRD）, high-resolution scanning electron microscopy （HRSEM）, atomic force microscope （AFM） and thermogravimetry-differential thermal analysis （TG-DTA）.The author designed a series of experiment against the new system by the research on the literatures. On the research of SiO₂-TiO₂ thin film, it was found that the addition of SiO₂ could suppress the structural phase transition and crystal growth of TiO₂ crystal. And the relationship between crystalline size and hydrophilicity under sunlight was investigated in this dissertation. Secondly, the results of the research on V₂O₅-TiO₂ films were similar to SiO₂-TiO₂ films-the introduction of V₂O₅ could suppress the structural phase transition and crystal growth of TiO₂ crystal too. What’s more important is that the dopant of V₂O₅ on TiO₂ thin films could produce a visible-light response to the films, the water contact angles decreased from 35° before irradiation to 8° after being illuminated by sunlight for 40 minutes while the those of pure TiO₂ thin films remained unchanged after irradiation. And the contact angles decreased as a whole with increasing the amount of V₂O₅ content. Finally, accordingto the results of the research on sensitivity mechanism, the visible response character was attributed to the 3d energy level of V element. Meanwhile, the V2O5 is a narrowband semi-conductor. When it combined with a wideband semi-conductor, TiO2, it could improve the efficiency of charge separation and expand the spectral response of T1O2.At last, the work in dissertation was generalized and the problems which were unsolved in paper were represented base of this. The orientation of research in future was pointed out.更多还原