特殊形貌zno制备及其光催化性能研究.doc

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摘   要

光催化处理有机废水技术是一项耗能低、易操作、且无二次污染，具有广阔应用前景的新技术。然而其实际应用仍然被光催化效率较低所限制，因此，发展高效光催化剂已经成为一项重要的研究课题。ZnO是一种高效、无毒性、价格低廉的重要光催化剂，在降解环境中的有机污染物领域备有着重要作用。众所周知，无机材料的形貌对其多样化的性能及其相应的应用有重要的影响，而ZnO是一种具有丰富多样形貌的宽禁带半导体材料。因此，制备特殊形貌的ZnO纳米材料，可以提高其光催化降解效率。

本文利用水热法制备出了花状形貌的纳米ZnO，分析了纳米ZnO的形貌与制备变量的关系。用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）对制备的纳米ZnO进行了表征。以罗丹明 B 降解为模型反应，评价不同形貌 ZnO的光催化性能，分析影响催化活性的因素，在多种表征基础上，对催化剂的结构与催化性能进行关联。比较了不同温度煅烧后的花状纳米ZnO的降解效率并分析了花状纳米ZnO的投加量对光催化性能的影响。

光催化降解罗丹明B的实验结果表明，具有较大比表面积的纳米ZnO形貌的样品具有较好的光催化性能。

关键词：纳米ZnO；光催化；水热法；机理；性能 

Abstract

Photocatalytic oxidation for organic wastewater treatment is a promising technology with low cost, easy operation and non-secondary pollution. However, it is limited to actual application due to the low photocatalytic efficieney. Therefore,the development of highly effective photocatalyst has become one of the most important research subjects.ZnO, as a well-known photocatalyst for its high efficiency,non-toxic nature and low cost, has been played a important role in the degradation and complete mineralization of environmental pollutants. The morphologies of inorganic materials are demonstrated to have great effects on their widely varying properties and corresponding potential applications. It is well known that ZnO exhibits the richest range of morphologies among the wide band gap semieonductors. Therefore, the fabrication of ZnO nanomaterials with special morphologies could effectively improve their photocatalytic activity.

In this paper we prepared porous flower-shaped morphology of nano ZnO by hydrothermal synthesis, analyzed the relationship between the morphology of nano ZnO and preparation variables. The as-prepared porous flower-shaped ZnO nanostructures were characterized by X-ray Diffraction(XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM). The eva luation of photocatalytic performance by using the degradation of Rhodamine B (RhB) as model reaction. The exploration of structure-performance relationship on the basis of multiple characterizations.Comparison of the degradation efficiency of nano ZnO calcined at different temperatures and analyzed influence of the photocatalytic performance of the dosage of flower-shaped nano ZnO.

The experimental results of photocatalytic degradation of Rhodamine B indicate that the sample of porous flower-shaped ZnO nanostructures with more surface area has a better photocatalytic performance.

KEY WORDS: porous flower-shaped ZnO nanostructures; photocatalysis; hydrothermal synthesis; mechanism; performance 

目录

前言 1

第一章 综述 2

    1.1纳米ZnO的结构及主要性能 2

    1.2纳米ZnO的国内外研究现状及发展趋势 2

1.2.1纳米ZnO的制备方法 2

1.2.1.1纳米ZnO的液相化学制备方法 3

1.2.1.2纳米ZnO的气相化学制备方法 4

1.2.1.3纳米ZnO的固相反应制备方法 4

1.2.2纳米ZnO的应用 5

1.2.3纳米ZnO未来的发展趋势[23] 7

    1.3光催化技术概述[24-26] 7

1.3.1光催化技术的概况与发展 7

1.3.2半导体光催化技术的基本原理 8

1.3.3提高光催化反应效率的途径 8

    1.4本课题的研究意义及内容 8

1.4.1研究意义 8

1.4.2研究内容 9

第二章 特殊形貌ZnO的制备与表征 10

2.1样品制备 10

2.1.1实验试剂 10

2.1.2实验仪器 10

2.1.3实验过程 11

2.1.4实验结果 12

2.2表征方法与表征结果 12

2.2.1表征方法 12

2.2.2表征结果与讨论 13

2.3纳米ZnO的可控生长机理 18

    2.4本章小结 20

第三章 纳米ZnO的光催化性能研究 21

    3.1引言 21

    3.2实验部分 21

3.2.1光催化反应装置 21

3.2.2反应污染物的选择 21

3.2.3实验过程 22

    3.3实验结果与讨论 22

3.3.1煅烧温度对纳米ZnO光催化性能的影响 22

3.3.2纳米ZnO的投加量对其光催化性能的影响 24

3.4本章小结 25

第四章 结论 26

参考文献 27

致谢 30