【作者】 唐鹏；

【导师】 沙作良； 黄岳祥；

【作者基本信息】 天津科技大学 ， 化学工程， 2015， 硕士

【摘要】 近年来,利用半导体材料光催化制氢和光降解有机污染物等技术,为人类提供了高效、清洁、可再生资源和有效治理环境污染的理想途径。作为半导体光催化剂的TiO₂具有高光催化活性、降解有机物效率较高、化学性质稳定以及不引起二次污染等优势,吸引了众多科研工作者的关注,但因其光响应能力缺陷（即因带隙宽而仅对波长X<387nm的光线具有明显光响应能力）以及光能利用率低,严重阻碍了二氧化钛的实际化学工业应用及推广。本文以二氧化钛为母体异质掺杂制得高活性的光催化复合材料并通过实验和模拟的方法探究了二氧化钛的光催化性能,主要研究内容及结论如下：首先,采用水热合成结晶法制备TiO₂,结合透射电子显微镜（TEM）、扫描电子显微镜（SEM）、 X射线粉末衍射（XRD）、X射线能谱（XPS）等手段的表征分析,可得知随水热结晶时间从1h延长至24 h、水热温度由353.15 K提高到453.15 K,分别制得无定形的板钛矿、锐钛矿,晶体粒度的大小也随着水热时间的延长、水热温度的升高而增大：同时分别以白制的TiO₂和德固赛公司气相沉积法制得的二氧化钛P25为母体,采用溶浸法异质掺杂CuO、Fe₂O₃改性TiO₂,并进行了SEM、TEM、XPS、UV-Vis（紫外可见光谱）等表征分析,获得了CuO、Fe₂O₃以及CuO和Fe203共改性TiO₂复合体系的颗粒粒径大小为18-30 nm、元素组成和价态分别为Cu⁺², Fe⁺³, O^-2。再次,分别于紫外光、可见光条什下对水热结晶制备的TiO₂、CuO、Fe₂O₃以及CuO和Fe₂O₃异质改性的TiO₂复合体系进行光催化分解水制氢和光催化降解甲基橙（MO）活性测试,并对不同制备方法和不同改性方法制得的样品（2CT、2FT、2CFT、CT2、FT2、CFT2、CP2、FP2及CFP2）进行了光催化降解MO反应,得出无论紫外还是可见光照射下,样品CFT2/2CFT/CFP光催化降解MO溶液的光催化活性明显优于CT2/2CT、FT2/2FT以及P25,还得出样品（CT2/FT2/CFT2）的光催化活性强于样品（CP2/FP2/CFP 2）的光催化活性依次强于水热法制得样品（2CT/2FT/2CFT）的光催化活性,归因于PN异质结拓展了二氧化钛的光响应范围和促进了光生电子和空穴（e^--h⁺）的有效分离。最后,在分析异质掺杂改性TiO₂光催化分解水制氢、降解MO的反应机理的基础上,首次运用量子化学模拟软件计算了铜／铁共掺杂锐钛矿二氧化钛的光电学性质,表明铜／铁共改性的TiO₂复合体具有量子协同效应。更多还原

【Abstract】 In recent years, semiconductor photocatalytic materials exhibit an ideal way of providing efficient, clean and regenerated resource and efficient environmental treatment. As one kind of photocatalysts, TiO₂ has been widely used for high photocatalytic activity, thoroughly photodegradation organics and chemical stability without secondary pollution. However, there are some problems during the practical chemical industrial application and promotion of TiO₂, owing to relatively wide band gap and narrow range of photoresponse （λ<387 nm）. In this dissertation, our main ideas are synthesizing, characterizing, and calculating the crystal structure and photocatalytic performance of TiO₂-based photocatalytic materials. The main points could be summarized as follows:Firstly, we synthesized TiO₂ by hydrothermal synthesis crystallization method and characterized their phase structures, surface property through Transmission Electron Microscopy （TEM）, Field Emission Scanning Electron Microscopy （SEM）, X-ray diffraction （XRD）, X-ray Photoelectron Spectroscopy （XPS）. Brookite and Anatase prepared as hydrothermal time and temperature increasing from 1 h to 24 h and from 353.15 K to 453.15 k, respectively, and the crystallite size of samples increased with hydrothermal time and temperature. At the same time, based on homemade TiO₂ and commercial Degussa P25, samples prepared by impregnation and calcination method and characterized by SEM, TEM, XPS, UV-Vis, Raman, getting to know the crystallite size of CuO and Fe₂O₃ is 5-10 nm, element composition and valence state is Cu⁺², Fe⁺³, O^-2, Ti⁺⁴ and discovering CuO, Fe₂O₃.The photocatalytic hydrogen production and degradation of methyl orange （MO） experiments were performed to test samples photocatalytic activity and contrastive analyzed photocatalytic activity of degradation MO reaction of samples （2CT,2FT,2CFT, CT2, FT2, CFT2, CP2, FP2 and CFP2 prepared by the different preparation and modification methods） under ultraviolet, visible light irradiation. It is concluded that both ultraviolet and visible light illumination, the photocatalytic activity of samples （CFT2/CFT2/CFP2） is superior to CT2/2CT, FT2/2FT and P25, and the photocatalytic activity of samples （CT2/FT2/CFT2） prepared by leaching method is stronger than that of CP2/FP2/CFP, in turn, is better than that of hydrothermal synthesized samples （2CT/2FT/2CFT） for PN heterojunction expanding the titanium dioxide photoresponse range and promoting effective separation of the photogenerated electrons and holes （e^--h⁺）.Finally, based on the analysis of the reaction mechanism of photocatalytic water splitting and MO degradation of heterogeneous doping modification TiO₂, the photoelectric property of copper/iron codoped anatase titanium dioxide was investigated using quantum chemical principle （Density Functional Theory, DFT）, showing that the synergistic effect of Cu and Fe co-doping anatase TiO₂ according to the properties of electronic and optical results in the modification TiO₂ complex, indirectly proofing PN heterojunction contribution photoproduction e--h+the of separation from quantum chemical theory.更多还原