【作者】 杨露；

【导师】 刘鹏；

【作者基本信息】 武汉理工大学 ， 应用化学， 2011， 硕士

【摘要】 Ti02光催化材料由于具备活性高、价格低廉、性质稳定等特性已经成为21世纪在环境净化、水体处理等方面开发应用比较有价值的材料。但是具有较高活性的锐钛矿晶型二氧化钛的禁带宽度约为3.2eV,使得活性二氧化钛在实际中的应用受到了很大限制。另外,由于合成的二氧化钛被光激发所产生的电子和空穴的高重新复合率,使得其对污染物质的光催化效率不高(量子产率低下)。提高Ti02的光催化效率及光响应范围的方法及手段很多,主要有半导体复合、染料敏化、贵金属沉积、离子掺杂和双元素共掺杂。由此,本论文通过不同的方法合成不同掺杂二氧化钛光催化材料,以一些分析手段来评价掺杂二氧化钛的物理化学性质。具体研究内容和结果如下：(1)以钛醇盐的水解法和溶胶-凝胶法合成纯二氧化钛和掺杂二氧化钛,且研究加水量对凝胶形成的影响。通过正交实验的方法研究了加水量对钛醇盐水解及形成凝胶的影响,确定了凝胶-凝胶法合成纳米Ti02光催化材料的最优配比为：M钛酸丁酯:M无水乙醇:M冰醋酸:M去离子水=1:18:2:3.5(摩尔比),并以同样的方法确定了钛酸丁酯的水解条件。(2)利用钛醇盐的水解法制备了一系列Nd和I掺杂Ti02光催化材料,Nd和I掺杂二氧化钛光催化材料的物理性质通过X射线衍射(XRD)、紫外-可见(UV-vis)漫反射、扫描电镜(SEM)和X射线能谱(EDS)分析,在合成过程中考虑了Nd和I掺杂比例和煅烧温度对二氧化钛光催化活性的影响；以亚甲基蓝(MB)和牛血清白蛋白(BSA)考察合成掺杂二氧化钛的光催化活性,以大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)为考察对象考察所制备光催化材料的抗菌性能。结果表明,Nd掺杂能够阻止Ti02晶粒生长,并使Ti02在可见光区有几个很强的吸收峰谱(528、587 683、750、808、881 nm),这主要是由于Nd的4f电子结构所引起的。I掺杂可以极大的扩展TiO2在可见光区的响应,通过Nd和I共掺杂可以使掺杂Ti02在可见光区的能带最小扩展到2.82ev(MNd：MI：MTi=5：10：100(摩尔比))。在300W碘钨灯下对MB光催化降解和对BSA损伤有最高光催化活性掺杂Ti02掺杂比例为MNd：MI：MTi=5：10：100(摩尔比),其对MB的降解速率为3.86×10-2min-1约是纯TiO2(2.28×10-3min-1)的17倍；最佳掺杂比例材料的抗菌性主要是通过破坏E.coli和S.aureus的表面细胞膜而杀死E.coli和S.aureus.(3)利用溶胶-凝胶法制备一系列Nd和F掺杂Ti02光催化材料,Nd和F掺杂二氧化钛光催化材料的性质表征与(2)中所用方法一致,在合成过程中考虑了Nd和F掺杂比例和煅烧温度对二氧化钛光催化活性的影响；以亚甲基蓝(MB)考察合成掺杂二氧化钛分别在紫外光和可见光下的光催化活性。结果表明,Nd掺杂在Ti02中所起的作用与(2)中一样；F掺杂可以使TiO2晶型生长和结晶完整,且可以使Ti02吸收带隙红移和增强其在紫外光区的吸收,其中TiF5Nd0.5发生了最大红移,通过计算其能带为2.91eV。在紫外光激发下,对MB的光催化降解速率最高的材料为TiF5Nd0.5,其降解反应速率常数约为纯Ti02的1.76倍；在可见光激发下,对MB的光催化降解速率最高的材料同样为TiF5Nd0.5,其降解反应速率常数约为纯Ti02的1.45倍。更多还原

【Abstract】 Because of high activity, low prices and stable of TiO2 photocatalytic material, it has become more valuable materials in the 21st century. It can be applicated in the purification, water treatment and other aspects in our environment. But the band gap of titanium dioxide is about 3.2eV, this result the practical application of it has been greatly restricted. In addition, titanium dioxide could produce electron and hole by excitate of light, but the recombination rate of electron and hole are very high which decreased the photocatalytic efficiency to pollutants (the low rate of quantum yield). Many methods can improve the photocatalytic efficiency such as semiconductor compound, dye sensitization, noble metal deposition, ion doping and double element doping, thus, we synthesized different doped titanium dioxide photocatalyst by different methods in our study. At the same time, we evaluate the physical and chemical properties of doping titanium dioxide. The specific contents and results are as follows:(1) pure titanium dioxide and doped titanium dioxide are synthesis by Hydrolysis of titanium alkoxide and sol-gel method; Moreover, we also study the relation between the amount of water and the gel formation time. The amount of water on the titanium alkoxide solution and the formation of the gel were study by orthogonal experimental method. The optimal ratio of nano-TiO2 photocatalyst was determined by sol-gel synthesis, and the result is that Mn-butyl titanate:Methanol:Macetic acid:Mdeionized water= 1:18:2:3.5 (molar ratio). Meanwhile, the hydrolysis of butyl titanate was determined by the same method.(2) A series of Nd and I doped TiO2 photocatalyst were synthesized by the hydrolysis of titanium alkoxide. The characteristics of neodymium and iodine doped TiO2 were evaluated by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, scanning electronic microscope (SEM) and Energy Dispersive X-Ray Spectroscop-y (EDS). In the synthesis process, Nd:I:TiO2 with different doping content (molar ratios) calcined at different temperature was designed. The photocatalysis activity was evaluated by methylene blue (MB) and bovine serum albumin (BSA), and the mold resistance was evaluated by colibacillus (E.coli) and Staphylococcus aureus (S.aureu- s). The results show that Nd doped TiO2 can prevent the growth of it, and has intense absorption at 528,587,683,750,808, and 881 nm, this phenomenon mainly due to the 4f electron structure of Nd. I doping can extended the response vastly of TiO2 in visible region, Nd and I co-doped TiO2 can extend the band of TiO2 to 2.82 eV (MNd:MI:MTi=5:10:100 (Molar ratio)). MNd:MI:MTi=5:10:100 (molar ratio) has highest photocatalysis activity by photocatalytic degrade MB and BSA in 300 W tungsten, and the degradation rate of MB (3.86×10-2 min-1) is about 17 times compared to pure TiO2 (2.28×10-3 min-1). The mold resistance of optimum photo-catalyst could kill E.coli and S.aureus through damaging their outer membrane (even deteriorated completely) by their radiation of light.(3) A series of Nd and F doped TiO2 photocatalyst were synthesized by the sol-gel method. The characteristics of neodymium and fluorine doped TiO2 were evaluated by the same method with the above (2). In the synthesis process, Nd:F:TiO2 with different doping content (molar ratios) calcined at different temperature was designed. The photocatalysis activity was investigated by methylene blue (MB) under ultraviolet and visible light, respectively. The results show that Nd doping has the same effect with the above (2). F doping can makes crystal growth and crystallization complete of TiO2, and it also can make the band gap red shift of TiO2. TiF5Nd0.5 has the maximum redshift, and it band gap was calculated about 2.91 eV. In the UV-irradiation, TiF5Ndo.5 has the highest photocatalytic degradation rate to MB, and it degradation reaction rate constant was about 1.76 times than pure TiO2; in the visible light motivate, TiF5Nd0.5 also has the highest photocatalytic degradation rate to MB, and it degradation reaction rate constant was about 1.45 times than pure TiO2.更多还原