【作者】 王存；

【导师】 傅家谟； 盛国英； 赵进才； 王新明；

【作者基本信息】 中国科学院研究生院（广州地球化学研究所） ， 地球化学， 2002， 博士

【摘要】 环境污染问题是当今世界的主要问题之一。在工业和家用废水中常常发现有机污染物。这些有机物在被排放到环境中之前，须先加以破坏或清除。地下水和水源水也常常发现一些有机污染物。要使受到污染的地下水和水源水合乎饮用水标准，也须做必要的处理。公众对环境污染问题与日俱增的关心，推动了环境治理新方法的诞生和发展，光催化就是日益受到关注的新兴环境治理方法之一。 将受激半导体用于降解水和空气中的有机污染物，不仅在理论上已经做过充分的研究，在实践上也被成功地用来处理过大量的化合物。在实验室和实际应用研究中发现，能够被光催化过程破坏的有机物有：醇、羧酸、胺、除草剂、醛等。光催化能够使有害有机物发生矿化作用生成二氧化碳、水和简单的矿物酸。因此，与现有的技术相比，光催化过程的主要优点之一是不需二次处理。 光催化过程的另一个优点是，与使用过氧化氢和臭氧等氧化剂的其他高级氧化技术相比，光催化过程不需要使用昂贵的氧化剂，因为空气中的氧就是它要使用的氧化剂。光催化剂还可以再生和循环利用。 还可以利用太阳光引发的光催化过程来破坏某些有机污染物。这种情况下，光催化过程的运行成本很低。 理想的光催化剂应当稳定性好，价格低廉，无毒性，高活性且能充分吸收太阳光。 近年来，很多研究的焦点都放在二元或三元复合氧化物上，希望找到电荷分离效率高，光响应的范围宽，因而光催化效率高且能充分吸收利用太阳光的光催化剂。 本论文继续沿着这个方向做积极的探索，并发现了一些有趣和有益的成果。 本论文主要包括4部分： 1．简要介绍了光催化剂的光催化活性原理。对光催化剂的改性，包括金属离子掺杂、表面敏化、粘土交联和复合氧化物半导体等的近期进展，做了简要的介绍。对纳米光催化剂的基本原理、基本性质以及近期进展，也做了简要的介绍。 2．采用共沉淀法合成纳米Zn₂SnO₄。研究了纳米Zn₂SnO₄的合成条件及其烧结过程和机理。用X射线衍射（XRD）、透射电子显微镜（TEM）、差热和热失重分析（TG-DTA）和比表面积（BET）对Zn₂SnO₄做了表征。求出纳米Zn₂SnO₄的晶粒生长活化能为337.9kJ／mol。建立了Zn₂SnO₄的晶粒生长方程为：D^4.78=9.12×10²³texp（-40.6×10³／T） 用纳米Zn₂SnO₄作光催化剂降解水溶液中的毒害有机物苯。研究表明：Zn₂SnO₄对苯有光催化活性，且Zn₂SnO₄的光催化活性与其粒子尺寸有关，这可用比表面积和尺寸量子理论予以解释。 3．采用共沉淀法合成了摩尔比为2:1（Z₂S₁）和1:1（Z₁S₁）的ZnO／SnO₂复合氧化物。用X射线衍射（XRD）、UV-Vis漫反射光谱和比表面积（BET）对Z₂S₁、Z₁S₁做了表征。用甲基橙（MO）作模型有机物对它们的光催化活性做了评估。研究了MO在Z₂S₁表面上的等温吸附行为。研究了热处理条件对Z₂S₁的光催化活性的影响。也研究了pH值、反应悬浮液中的电解质如NaCI、KNO。和K多O4对ZZ民的光催化活性的影响。通过UV－VS漫反射光谱求得乙S；、ZS；、ZnO、SnO。的禁带宽度（带隙能）分别为3．15、3．12、3．17和二．53eV。等温吸附线是一个T台阶曲线。ZZS；对 MO的光催化降解速率分别比 Z6和 ZnO快40．2％和 66．l％。提出一个电荷分离和光催化活性的原理示意图并用之对 民和乙S；的光催化活性做了合理的解释。 4．采用共沉淀法，通过调节不同的烧结温度，合成了不同Sn含量的纳米ZnO／SnO。复合氧化物。用X射线衍射(io＼UV－VIS漫反射光谱和比表面积（BET）对它们做了表征。发现：高温有利于形成较大晶粒尺寸的 ZnO侣nO。复合氧化物，较高的Sn含量有利于得到较大比表面积的ZnO用nO。复合氧化物。根据UV－Vis漫反射光谱计算出了不同Sn含量和不同烧结温度下的ZnO侣nO。复合氧化物的带隙能。发现带隙能随着Sn含量和烧结温度而变化。此外，用甲基橙（MO）作模型有机物，对 ZnO沼nO。复合氧化物的光催化活性做了评估。发现：含有33．3％的Sn和在700＊下烧结10h的ZnO侣nO。复合氧化物，表现出最大的光催化活性。更多还原

【Abstract】 Environmental pollution is one of the major problems of the modern world. Organic chemicals which may be found as pollutants in waste water effluents from industrial or domestic sources, must be removed or destroyed before discharge to the environment. Such pollutants may also be found in ground and source waters that also require treatment to achieve acceptable drinking water quality. The increased public concern with these environmental pollutants has prompted the need to develop novel treatment methods with photocatalysis gaining a lot of attention in the field of pollutant degradation.The application of illuminated semiconductors for degrading undesirable organics dissolved in air or water is well documented and has been successful for a wide variety of compounds. Organic compounds such as alcohols, carboxylic acids, amines, herbicides and aldehydes, have been photocatalytically destroyed hi laboratory and field studies. The photocatalytic process can mineralize the hazardous organic chemicals to carbon dioxide, water and simple mineral acids. Thus, one of the major advantages of the photocatalytic process over existing technologies is that there is no further requirement for secondary disposal methods.Another advantage of this process is that when compared to other advanced oxidation technologies, especially those using oxidants such as hydrogen peroxide and ozone, expensive oxidizing chemicals are not required as ambient oxygen is the oxidant. Photocatalysts are also self-regenerated and can be reused or recycled.Finally, the solar photocatalytic process can also be applied to destroy some organic compounds which means the process can be operated in a low cost.An ideal photocatalyst should be stable, inexpensive, non-toxic, highly photoactive and, of course, good visible light absorptive.hi recent years, many researches have focused on the binary or ternary metal oxide to find a more effective photocatalyst by increasing the efficiency of charge separationand extending the photo-responsing range.In this dissertation, we are motivated to work in this direction and finally find some interesting and useful results.This dissertation mainly includes 4 parts as follows:1. The photocatalytic principle of semiconductors used in air and water treatment is introduced, and some recent developments in the modification for the photocatalysts, including metal ion doping, surface sensitization, clay cross-linked semiconductors and coupled oxide semiconductors, are also introduced. Additionally, the principle and some recent developments of nano-sized photocatalyst are also introduced.2. Nano-sized Zn2SnO4 materials have been synthesized using the coprecipitation method. The synthetic conditions and the calcination behaviors of nano-sized Zn2SnO4 materials have been studied. The nano-sized Zn2SnO4 materials have been characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry and differential thermal analysis (TG-DTA) and specific surface area. As a result, the kinetic grain growth equation for nano-sized Zn2SnO4 can beexpressed as: Z)478 =9.12xl023fexp(-40.6xl03 IT), with an activation energy forgrain growth of Q=337.9 KJ/mol. The nano-sized Zn2SnO4 materials have been used as photocatalysts to decompose benzene in water solution. The results show that Zn2SnO4 can photocatalytically decompose benzene, and the photocatalytic capacity for Zn2SnO4 relates to the grain size, which is discussed in terms of the surface effect and the quantum size effect.3. The nano-sized coupled oxides ZnO/SnO2 in a molar ratio of 2:1 (Z2St) and ZnO/SnO2 in a molar ratio of 1:1 (ZjS,) were prepared using the coprecipitation method and characterized with X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy and specific surface area (BET). Their photocatalytic activities were also evaluated using methyl orange (MO) as a model organic compound. The isothermal adsorption behavior of MO on Z2S,, and the factors affecting the photocatalytic activity更多还原