【作者】 熊忠华；

【导师】 魏锡文；

【作者基本信息】 重庆大学 ， 物理化学， 2002， 硕士

【摘要】 本文以钛酸丁酯为前驱体，利用溶胶—凝胶法制备了纳米级的TiO₂粉体材料，通过正交实验研究了醇盐的浓度、溶剂的种类、水含量、水解温度、干燥条件和煅烧温度等工艺条件对纳米粒子的比表面积、粒径大小及分布、晶相组成等性能的影响。实验表明，合适的反应条件是：以醋酸为负催化剂，水解温度应控制在30℃左右，钛酸丁酯与水量、溶剂量的配比应为1：4：10。另外得到比较单一的锐钛型TiO₂煅烧温度应控制在600℃左右。 本文选择过渡金属离子Fe³⁺、Co²⁺、Ni²⁺、Ag⁺、Cu²⁺、Cr³⁺分别以不同的质量比对TiO₂进行掺杂，研究催化剂的修饰。对次甲基蓝的降解实验表明掺杂离子的修饰效果与过渡金属离子的离子半径、外围电子构型、氧化还原电位和离子浓度等因素有关，质量比为0.5％的Fe³⁺掺杂对次甲基蓝的降解效率最高。纳米TiO₂-V₂O₅复合光催化剂对次甲基蓝的降解实验表明，复合V₂O₅后TiO₂可以加速电子捕获和电荷迁移速率，改变了样品表面吸附亲合力，使降解效率相比纯TiO₂有很大提高。同时本文利用化学复合镀在钢铁基体上形成Ni-P-纳米TiO₂复合镀层，该复合镀层对次甲基蓝有较好的光催化降解作用，其催化性能与粉末状纳米TiO₂的催化性能大致相当。 选取不同尺度的簇模型从头计算表明，随着尺度的减小量子尺寸效应越发显著，费米能级附近的能级间隔变大，能级分立现象更加明显。对吸附在TiO₂表面的苯胺分子构型的从头计算研究表明，由于氨基的引入对苯环C-C键长以及苯环各原子净电荷密度有一定的影响。苯胺分子的光催化氧化可分为三个阶段：苯环羟基化，生成羧酸和生成二氧化碳。从头算的结果显示在羟基自由基的进攻下苯环羟基化反应和生成羧酸的反应只需克服较小的能垒。反应的最终产物将以二氧化碳为主。更多还原

【Abstract】 The nanoparticle titanium dioxide was prepared with TNB as rawmaterial by the sol-gel process, the effects of the alcohol salt concentration \the kind of solvent \ the water volume \ hydro1yze temperature. the dried waysof the wet gel and the calcined temperature of the dry gel on the specificsurface area. particle size. particle size distributing and the composing ofcrystal phase were discussed by the orthogonalizing design.The experimentsshowed that the most suitable process conditions should controlled asfOllows: process temperature was about 30C; the ratio of TNB’ water andsolvent was l: 4: l 0: the calcined temperature was about 600 ’C.Such transition metal ions as Fe3+. Co2+. Ni2+. Ag+. Cu2+. Cr3+ wereselected with different weight ratio doping in TiO2 to study the photocatalystmodifying in this paper.The experiments of degradation methylene blueshowed that the doping results were quantitatively correlated with thetransition metal ion radii. their electronic configuration. the oxide and reducepotential and the dopant concentration.The experiments of degradation methylblue a1so showed that the photocatalytic activity could be greatly improvedwith VzOs-loaded TiO2, maybe that loading V2O5 would accelerate theelectron captured and charge transferring, change the samp1e surfacehydrophilic and absorption. Nanometer TiO2 particles were well distributed inNi-P plating layer on steel surface by electroless plating.’ The study showedtheir effects on photocatalytic degradation fOr methylene blue were equa1 tothe TiO2 powder capability of photocatalytic.The ab initio calcu1ation by selecting cluster mode1 with different sizeshowed that with the decrement of model size the quantum-sized effect wasmore prominence, the energy distance was bigger near fermi energy, theenergy schism was also more obvious. The ab initio study of aniIine molecularstructure which adsorbed in the TiO2 surface indicated that the C-C bondlengths and the atomic charge density were affected by the amino importing,the ani1ine molecular photocatalyst oxidation included three phases: benzenering hydroxidation, producing carboxyl acid and producing CO2, the ab initiocalcu1ation results showed that the reactions of benzene ring hydroxidationIIN&xe7@fJ%{yiAxand producing carboxy1 acid were required to get over 1esser activation energywith the .OH.attracting .The mostly ultimate products were CO2.更多还原