纳米二氧化钛基光催化剂的制备及其性能研究
文献类型：学位论文
| 作者 | 张军玲
|
| 学位类别 | 博士 |
| 答辩日期 | 2008-10-25 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 袁章福 |
| 关键词 | 纳米二氧化钛 光催化 负载 改性 动力学 |
| 其他题名 | Study on Preparation of Nanosized TiO2-based Photocatalyst and Its Properties |
| 学位专业 | 化学工艺 |
| 中文摘要 | 纳米TiO2因其独特的光催化性能在环境污染治理方面具有广阔的应用前景。但在实际应用中纳米TiO2存在回收困难、易团聚、光吸收范围窄和能量利用效率低等问题。针对上述问题，本研究进行了纳米氧化钛基光催化材料的制备、负载和改性研究，进而完成了模拟污染物光催化降解实验的研究。此外，还对材料结构、性能以及光催化过程从动力学和反应机理方面进行了系统的分析。 本论文取得如下创新性研究成果： (1) 用一种改进的过氧钛酸为前驱体的溶胶-凝胶法制备出锐钛型TiO2，该方法是把一定量的水加入到四氯化碳的乙醇溶液中，以缓解TiCl4与水反应的剧烈程度，摆脱了以往在制备TiCl4溶液时需要在冰水浴中的操作，降低了能耗。采用热重分析可以推断出干凝胶的化学构成：TiO1.3(O2)0.5(OH)0.4•1.6H2O。XRD和SEM分析结果表明，600℃下的热处理效果最好。把所得胶体负载到载玻片上再进行热处理，可得到光催化活性较高的锐钛型光催化膜。 (2) 采用共沉淀和溶胶凝胶法制备了Fe、V双金属离子掺杂的光催化TiO2薄膜，当Fe、V金属离子共掺杂总量为0.05%时，掺杂薄膜上颗粒较小，且在紫外光的照射下表现出超亲水性。当Fe3+和V5+共掺杂紫外-可见吸收出现了新的红移吸收峰。对掺杂薄膜亲水性能和光催化降解甲基橙活性的研究表明Fe、V离子共掺杂最佳比为1: 1，此时光催化降解甲基橙的效率较掺杂前提高了93.4%。 (3) 采用阳极氧化法制备了管径均匀的二氧化钛纳米管阵列。400°C热处理后的样品属于锐钛矿型，具有良好的光催化活性。采用贵金属Pt和Ag进行改性，通过提高电子空穴的分离来提高其光催化效率。紫外可见吸收测试表明，贵金属Pt、Ag沉积改性后的吸收峰面积较改性前分别提高了72%和183%。分别以甲基橙和甲醛为目标降解物催化降解反应中，光催化活性顺序均为Pt/TiO2 >Ag/TiO2 >TiO2，反应动力学分析发现甲醛的降解较甲基橙更符合一级动力学反应模型。 (4) 首次采用静态界面法在水/离子液体界面一步合成了中空二氧化钛微球。本研究具有四个突出的优点：1) 界面反应是一种简单，高效的一步合成方法，制得的中空球体尺寸可通过改变TiCl4初始浓度和反应温度等工艺参数进行调控；2) 热处理后所得锐钛矿型TiO2球体完整；3) 可拓展为其他易水解盐的离子液体溶液来制备功能材料；4) 可以在成球的同时对TiO2球进行金属离子掺杂改性以提高其光催化效率。 |
| 英文摘要 | TiO2-based photocatalyst has become increasingly promising technology in the wastewater treatment as a kind of novel functional material for its excellent photocatalytic activity. But many unresolved problems have restricted its large scale application in industry, such as difficult to recycling, tends to aggregate, narrow light absorption spectrum and low photocatalytic activity. Therefore, the present work was carried out for the investigation of preparation of TiO2-based photocatalyts，the immobilization methods and photocatalytic degradation of methyl orange (MO) and formaldehyde (analysized theoretically. Some new results has been made as follows: (1) Anatase TiO2 was prepared by the modified sol-gel method from peroxo titanic acid precursors. This method involved adding water into TiCl4/ ethanol solution at room temperature, which could reduce energy consume compared with the temperature control (0~5°C) process in the conventional peroxo titanic acid method. The composition of the dried gel is TiO1.3(O2)0.5(OH)0.4•1.6H2O which can be deduced by TG results. SEM and XRD indicated that anatase film formed by heating at 600°C. The anatase films which immobilized from PTA gel with smooth surface and high photocatalytic activity for degradation of methyl orange under UV irradiation. (2) Fe and V ions doping and co-doping films were prepared by using a modified PTA sol-gel and co-precipitation method. It was deduced that Fe and (or) V doping TiO2 films with mole ratio of 0.05% has smaller partical size and better wettability. The films became superhydrophilic after irradiation of UV light. TiO2 films co-doped by Fe and V exhibited a new absorption peak. The absorption peak red shifting which resulted in using effectively of sunlight. Photocatalytic activity of the films was also enhanced by doping Fe and (or) V ions for they can quicken the transition of photogenrated hole reaction and electron reaction on the surface, respectively. When the co-doped Fe and V ions with mole ratio of 1: 1, the film has the highest photocatalytic effeciency which increased by 93.4% compared with that of undoping TiO2 films for methyl orange under UV-vis irradiation. (3) TiO2 nanotube arrays which have uniform diameter and high surface area and trace of F and S in the phase were prepared by the anode oxidation method. Anatase phase was detected for samples heated at 400 °C. Pt and Ag were coated on the surface of anatase films to enhance the electron- hole pair separation. Absorbance area of photocatalyst with Ag and Pt deposits can be increased by 72% and 183% compared with pure TiO2 nanotubes. The photocatalytic degradation of MO and HCHO under UV-Vis irradiation was consistent well with the UV-Vis DSR which was ranked as follows: Pt/TiO2 >Ag/TiO2 >TiO2. The reaction kinetics analysis show that the regression correlation coefficient (R) of degradation curves of HCHO is fits better than that of MO with the first-order exponential decay curve. (4) A single-step synthesis of hollow titania microspheres on static interface of water/ ionic liquids were carried out in this work. The significance of the research is four fold. First, the interfacial reaction in the static interface provides an efficient, simple, one step route to the inorganic hollow microspheres. The size of hollow spheres can be controlled by physical conditions such as initial concentration of TiCl4 and temperature. Second, anatase spheres of TiO2 are stably obtained after calcination. Third, this technique is widely applicable to the reactive metal alkoxied for prparation of founctional materials. Fourth, the hollow titania gels can be simultaneously modified with metal ions to improved its photocatalytic efficiency. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 149 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1202]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 张军玲. 纳米二氧化钛基光催化剂的制备及其性能研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2008. |
入库方式： OAI收割
来源：过程工程研究所
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