【作者】 张旭；

【导师】 丁士文；

【作者基本信息】 河北大学 ， 无机化学， 2009， 硕士

【摘要】 二氧化钛是一种重要的半导体光催化材料,具有光催化活性好、耐腐蚀能力强、本身稳定性高、价格相对较低以及对人体无毒等优点,在光催化降解有机物方面显示了优良的特性,因而在环境污染防治、水处理、空气净化、制备自清洁材料等许多领域有着广阔的应用前景,成为材料学及催化科学研究的热点。然而TiO2是宽禁带材料,光谱响应范围较窄,对太阳能的利用效率较低,而且难于过滤及回收,在很大程度上限制了它的实际应用。为了提高TiO2的实用性,本文做了如下工作：设计了过渡金属离子掺杂工艺,对铈掺杂TiO2纳米材料进行了研究。实验中以廉价、易得的普通无机盐为原料,采用水热法合成了纳米CeO2-TiO2粉体,并对所合成的粉体进行了表征。X-射线衍射分析结果证明,水热法合成的产品为四方晶系锐钛矿结构,用透射电子显微镜(TEM)观察粒子基本呈球形,粒径20nm左右。应用实验证实改性后的粉体具有更高的反应活性,提高了光催化降解有机染料的速度和效率。基于介孔材料的发展,我们除了借助介孔分子筛的大比表面积来提高催化剂的吸附能力外,还通过金属元素的掺杂来促使TiO2光生电子与空穴的分离,双向提高其光催化效率和光谱响应范围。本文以表面活性剂十六烷基三甲基溴化铵(CTAB)与聚乙二醇或OP乳化剂为复合模板剂,利用水热法制备了一系列铈掺杂的二氧化钛介孔材料,并对影响反应的多种因素进行优化,确定了最佳反应条件。利用X-ray衍射仪进行物相分析,证明产品为四方晶系锐钛矿结构,用TEM观察样品形貌为无序介孔材料,可以很清楚地看到蠕虫状的无序孔道。产品的N2吸附一脱附等温线形状为LangmuirⅣ型,是典型的介孔结构吸附脱附等温线,并计算得到它的孔径在10-20nm之间。光吸收及吸附实验表明：水热法合成的纳米CeO2-TiO2复合介孔材料的吸附性能均优于同法合成的非介孔产品,并且证实：介孔粉体在紫外和可见光区都具有比非介孔纳米TiO2粉体更高的光吸收性能。光催化应用实验表明：本实验合成的纳米CeO2-TiO2复合介孔催化剂在太阳光照射下在40min以内就可完成对有机染料的接近100%脱色降解,比非介孔纳米TiO2粉体的脱色降解时间缩短了近一半。而对粉体的回收再利用实验证明：介孔粉体的过滤速度快,回收率高,而且重复利用效果也比非介孔纳米ZiO2粉体要好。更多还原

【Abstract】 Titanium dioxide is a kind of important semiconductor photocatalysis material and it has many advantages, such as high activity, anti-photochemical and chemical erosion, well stability, correspondingly low price and intoxicity. Many organic molecules will be photo-degraded completely by photo-catalyst TiO2, so it has offered considerable potential for wide use in many fields such as prevention and cure to environment pollution, water treat with, air purifying, the preparation of self-cleansing materials. As more attention is paid to environmental protection, photocatalysis material TiO2 has been focus on material science and catalysisology. However, TiO2 is a wide band gap materials, narrower spectral response, the less efficient the use of solar energy, but also difficult to filter and recycling, to a large extent limited its practical application. In order to improve the practicality of TiO2, woke below was done in this paper:The techniques of transitional metal ions doping was designed in my research work. The synthesis methods of doped TiO2 were probed in the first instance. Taking simple and low-cost inorganic salts as raw materials, nanometer-sized TiO2 powdes modified with Ce doping were prepared by normal pressure hydrothermal method. XRD analysis showed that they had tetragonal anatase structure. The powders are less aggregation and symmetrically ball-like through TEM analysis and particle size is about 20 nm. The applying experiment testified that modified TiO2 had higher reaction activity and velocity and efficiency of degration towards organic dyes.Based on the development of the mesoporous materials, we not only improve catalyst’s absorption capacity by virtue of high specific surface areas of materials, but also by way of the metal element doped TiO2 photovoltaic to impel the electronic and cavity separation, in order to enhance photocatalysis’ efficiency and widen spectral response range of TiO2 from two aspects. So in this article, mesoporous materials TiO2 with Ce adulterated were prepared by hydrothermal method, through joining surfactant CTAB with PEG or emulsifier OP composite template. Meanwhile, the best crafts parameters were obtained through optimizing various factors influencing the reaction. The structure of the synthesized product was discussed by XRD analysis; proved that the products belong to the Department of tetragonal anatase structure. TEM observation of samples used for the disordered morphology of mesoporous materials, can clearly see that the vermiculate ostium. Products’ N2 adsorption- desorption isotherms curve was the LangmuirⅣshape type, was a typical mesoporous structure of the adsorption-desorption isotherm curve and calculated its size was between 10-20nm. Optical Absorption and Adsorption experiments show that:Hydrothermal Synthesis of Nano-CeO2-TiO2 composite mesoporous materials were superior in the adsorption properties than the non-synthesis with mesoporous products, and confirmed:Mesoporous materials in the UV and visible light district had higher light absorption performance than the non-mesoporous nano-TiO2 powder. Photocatalytic experiments showed that:the compositive Nano-CeO2-TiO2 composite mesoporous catalyst in this experiment in the sunlight in less than 40min to complete decolorization and degradation the organic dye can be close to 100%, compared with the non-mesoporous nano-TiO2 powder decolorization and degradation of the time by nearly half. On the powder proved recycling:the mesoporous powder filterd fast, high recovery, and reuse effect of the mesoporous powder was better than the non-mesoporous nano-TiO2 powder.更多还原