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摘要在本实验中，Ag/TiO2纳米复合材料的合成方法主要为溶胶-凝胶法和原位还原法。首先，我们利用超声波处理粗混合溶液制成均匀的、含有银盐（AgBF4）的反相细乳液，然后将钛的前驱物（乙醇钛：TEO）直接加入该反相细乳液中进行聚合反应，形成AgBF4/TiO2纳米复合粒子，最后加入肼（水合联氨）作为高效还原剂，通过Ag+的原位还原制成Ag/TiO2。在该还原过程中，每一个小液滴都可以看做是一个纳米反应器，这也是反相细乳液体系的一个重要特点，使反应效率大大提高的同时也使产品尺寸更均匀、分散性更佳。之后我们通过各类形态学表征方法得到的一系列数据表明，Ag纳米粒子主要附着于TiO2纳米载体的表面，这是因为肼的还原效率非常高，使之刚刚接近TiO2的表面就与Ag+开始了还原反应。Ag/TiO2纳米复合材料具有多种晶型，通过在不同温度下煅烧我们得到Ag/锐钛矿型TiO2（400°C煅烧）和Ag/金红石型TiO2（900°C煅烧），煅烧前为Ag/无定形型TiO2。之后通过降解罗丹明B的可见光催化活性实验，我们得知其中的无定形型和锐钛矿型Ag/TiO2纳米复合材料具有高的可见光催化活性，并且其光催化活性高低受到Ag装载量的影响，而Ag装载量可以较为简便地通过改变AgBF4的装载量进行调节。最后我们系统地研究了不同的AgBF4装载量对Ag/TiO2纳米复合材料性质的影响。47350
毕业论文关键词：反相细乳液；Ag/TiO2纳米复合材料；可见光纳米光催化剂；溶胶-凝胶法；还原反应
Abstract
Ag/TiO2 nanocomposites were prepared through sol–gel process and situ reduction in this experiment. First of all, we used ultrasonic to prepare the inverse miniemulsions, which included silver salts; thereafter, TEO was directly introduced to the prepared inverse miniemulsions as titanium precursor, and then the AgBF4/TiO2 was formed; finally, add hydrazine as highly-efficient reducer to prepare Ag/TiO2 by situ reduction. In the reduction process, every water-drop in the inverse miniemulsions could be regarded as an “nanoreactor”, this is also one of the quiet important characteristics of the inverse miniemulsions, so that the reaction can be more efficient and the product can be well-distributed in solution, what is more, the nano-particles will form in almost the same size. The morphological investigation showed that Ag nanoparticles were mainly located on the surface of TiO2 nano-supports because of the fast reduction rate of Ag ions by hydrazine. When the hydrazine molecules went close to the surface of TiO2, the reaction would begin immediately. Ag/TiO2 nanocomposites have many phase, we got anatase TiO2 phase and rutile TiO2 phase by calcination at 400°Cand 900°C, and before calcination the phase of TiO2 was amorphous. By the photocatalytic experiment of degradation of Rhodamine B, we knew that the amorphous or anatase TiO2 phase displayed high visible-light catalytic activity, and the photoactivity was influenced by the content of Ag nanoparticles on the surface of TiO2 nano-supports. The content of Ag nanoparticles could be conveniently tuned by the loading of silver salts. Finally, the influence of the loading of silver salts on the particle properties of the Ag/TiO2 nanocomposites was investigated systematically.
Key words: Inverse miniemulsion; Ag/TiO2 nanocomposites; Visible-light nano-photocatalyst; Sol-gel; Reduction
目 录
摘 要 I
Abstract II
1.前言 1
1.1. TiO2纳米材料.1
1.2.反相细乳液2
1.3.课题的提出3
2. Ag/TiO2纳米复合粒子的合成与表征 3
2.1.实验部分
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