溶液燃烧法制备ZnO纳米结构及光催化性能研究

发布时间：2018-05-26 13:43

本文选题：溶液燃烧法 + 凝胶反应　；参考：《兰州大学》2015年硕士论文

【摘要】：溶液燃烧法是燃烧法的一种,溶液的成分主要由金属离子的盐类作为的氧化剂,有机化合物作为的燃料组成,溶液在不同的环境下经过燃烧后形成相应的化合物。溶液燃烧法主要运用于制备金属氧化物、碳化物、氮化物、硼化物、铝化合物等纳米材料。溶液燃烧法中不需要提供能够让金属化合物结晶所需的所有热量,只需要用达到燃料燃点的温度来引起燃料燃烧,通过燃烧释放出的热量使化合物结晶形成不同的结构得到产物。常用的溶液燃烧法有两个步骤：(1)大多数的溶液配置过程包含溶液向胶体转换并最终形成凝胶的过程；(2)燃烧过程。因此最终溶液燃烧会成为凝胶燃烧。通常实验中的前驱体溶液经过凝胶反应形成由金属盐与醇类组成的螯合物。目前关于溶液燃烧法的研究报告很多,但由于溶液燃烧法的反应速率非常快,很难控制产物的形貌、尺寸、结构、分散性等,而在纳米材料中上述参数通常对性能有着决定性的影响,因此针对这些问题提出改进方法也是现在溶液燃烧法的主要研究课题。纳米ZnO具有非常优良的物理和化学性能,并且根据文献记载纳米ZnO的形貌非常多,随着实验条件的轻微改变就能体现在形成的ZnO纳米结构上。因此本工作的设计是通过溶液燃烧法制备纳米ZnO,通过改变实验条件达到控制ZnO的纳米结构的目的,并通过光催化辅助了解每种ZnO纳米结构的光催化性能。(一)传统的溶液燃烧法制备ZnO纳米结构传统的溶液燃烧法主要是指在反应过程中形成凝胶,本文中的凝胶方法为Pechini法。前驱体的成分为硝酸锌、柠檬酸、去离子水和乙二醇。前驱体通过金属硝酸盐与柠檬酸的醇溶液形成螯合物的方式将溶液转变成凝胶,之后对凝胶进行燃烧制备ZnO纳米结构。在实验设计中,分别对硝酸锌与柠檬酸的质量比、去离子水与乙二醇的体积比及凝胶反应时间对ZnO纳米结构的影响等几方面进行了讨论,并对所形成的ZnO纳米结构的光催化性能进行了测试。(二) 以PVP为燃料的溶液燃烧法制备ZnO纳米结构以PVP为燃料的溶液燃烧法主要是指反应中没有溶液向凝胶转变的过程,实验主要是通过PVP模板的作用来形成ZnO纳米结构。前驱体溶液中的成分是乙酸锌、PVP、酒精与去离子水。将溶液搅拌成透明淡绿色时进行燃烧反应,前驱体溶液依旧呈胶状,但并不是形成凝胶,主要原因是由于PVP是一种大分子聚合物,溶解在溶液中呈现出一种粘稠的状态,没有凝胶形成是与传统溶液燃烧法的本质区别。在实验设计中,分别从反应温度、升温速率、乙酸锌加入量、酒精与去离子水的体积比对ZnO纳米结构的影响等几个方面进行了讨论,并对其不同ZnO纳米结构的光催化性能进行了研究。
[Abstract]:Solution combustion is a kind of combustion method. The composition of solution is mainly composed of salts of metal ions as oxidant and organic compounds as fuel. The solution is burned in different environments to form corresponding compounds. Solution combustion method is mainly used in the preparation of metal oxides, carbides, nitrides, boride, aluminum compounds and other nanomaterials. The solution combustion process does not need to provide all the heat needed to allow the metal compounds to crystallize; it only requires a temperature that reaches the fuel ignition point to cause the fuel to burn. The compounds are crystallized into different structures by the heat released by combustion. The common solution combustion method has two steps: 1) most of the solution configuration processes include the process of solution to colloid conversion and finally the formation of gel. Therefore, the final solution combustion will become gel combustion. The precursor solution in the experiment usually reacts with gel to form a chelate composed of metal salts and alcohols. At present, there are many reports on solution combustion method, but because the reaction rate of solution combustion method is very fast, it is difficult to control the morphology, size, structure, dispersity of the product, etc. The above parameters usually have a decisive effect on the properties of nanomaterials, so it is also the main research topic of solution combustion method to propose an improved method to solve these problems. Nanocrystalline ZnO has excellent physical and chemical properties, and the morphology of nanocrystalline ZnO is very numerous according to the literature. With the slight change of experimental conditions, it can be reflected in the formed ZnO nanostructures. Therefore, the design of this work is to prepare nanocrystalline ZnOs by solution combustion method, to control the nanostructures of ZnO by changing the experimental conditions, and to understand the photocatalytic properties of each ZnO nanostructure by photocatalytic assistance. (1) the traditional solution combustion method for the preparation of ZnO nanostructure mainly refers to the formation of gel in the reaction process. The gel method in this paper is Pechini method. The precursors are zinc nitrate, citric acid, deionized water and ethylene glycol. The precursor transformed the solution into a gel by chelating the metal nitrate with the citric acid alcohol solution, and then burned the gel to prepare the ZnO nanostructure. The effects of the mass ratio of zinc nitrate and citric acid, the volume ratio of deionized water to ethylene glycol and the gel reaction time on the ZnO nanostructures were discussed. The photocatalytic properties of the ZnO nanostructures were tested. (2) ZnO nanostructures were prepared by solution combustion method using PVP as fuel. Solution combustion method with PVP as fuel mainly refers to the process of transition from solution to gel in the reaction. The experiment mainly involves the formation of ZnO nanostructures by the action of PVP template. The precursors are zinc acetate PVP, alcohol and deionized water. When the solution is stirred to a translucent greenish green, the precursor solution is still colloidal, but not a gel. The main reason is that PVP is a macromolecular polymer that dissolves in the solution and presents a viscous state. No gel formation is essentially different from conventional solution combustion. In the experimental design, the effects of reaction temperature, heating rate, the amount of zinc acetate added, the volume ratio of alcohol to deionized water on the ZnO nanostructures were discussed. The photocatalytic properties of different ZnO nanostructures were studied.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O614.241

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