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摘   要

光催化處理有機廢水技術是一項耗能低、易操作、且無二次污染，具有廣闊應用前景的新技術。然而其實際應用仍然被光催化效率較低所限制，因此，發(fā)展高效光催化劑已經(jīng)成為一項重要的研究課題。ZnO是一種高效、無毒性、價格低廉的重要光催化劑，在降解環(huán)境中的有機污染物領域備有著重要作用。眾所周知，無機材料的形貌對其多樣化的性能及其相應的應用有重要的影響，而ZnO是一種具有豐富多樣形貌的寬禁帶半導體材料。因此，制備特殊形貌的ZnO納米材料，可以提高其光催化降解效率。

本文利用水熱法制備出了花狀形貌的納米ZnO，分析了納米ZnO的形貌與制備變量的關系。用X射線衍射（XRD）、掃描電鏡（SEM）、透射電鏡（TEM）對制備的納米ZnO進行了表征。以羅丹明 B 降解為模型反應，評價不同形貌 ZnO的光催化性能，分析影響催化活性的因素，在多種表征基礎上，對催化劑的結構與催化性能進行關聯(lián)。比較了不同溫度煅燒后的花狀納米ZnO的降解效率并分析了花狀納米ZnO的投加量對光催化性能的影響。

光催化降解羅丹明B的實驗結果表明，具有較大比表面積的納米ZnO形貌的樣品具有較好的光催化性能。

關鍵詞：納米ZnO；光催化；水熱法；機理；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 

目錄

前言 1

第一章 綜述 2

    1.1納米ZnO的結構及主要性能 2

    1.2納米ZnO的國內外研究現(xiàn)狀及發(fā)展趨勢 2

1.2.1納米ZnO的制備方法 2

1.2.1.1納米ZnO的液相化學制備方法 3

1.2.1.2納米ZnO的氣相化學制備方法 4

1.2.1.3納米ZnO的固相反應制備方法 4

1.2.2納米ZnO的應用 5

1.2.3納米ZnO未來的發(fā)展趨勢[23] 7

    1.3光催化技術概述[24-26] 7

1.3.1光催化技術的概況與發(fā)展 7

1.3.2半導體光催化技術的基本原理 8

1.3.3提高光催化反應效率的途徑 8

    1.4本課題的研究意義及內容 8

1.4.1研究意義 8

1.4.2研究內容 9

第二章 特殊形貌ZnO的制備與表征 10

2.1樣品制備 10

2.1.1實驗試劑 10

2.1.2實驗儀器 10

2.1.3實驗過程 11

2.1.4實驗結果 12

2.2表征方法與表征結果 12

2.2.1表征方法 12

2.2.2表征結果與討論 13

2.3納米ZnO的可控生長機理 18

    2.4本章小結 20

第三章 納米ZnO的光催化性能研究 21

    3.1引言 21

    3.2實驗部分 21

3.2.1光催化反應裝置 21

3.2.2反應污染物的選擇 21

3.2.3實驗過程 22

    3.3實驗結果與討論 22

3.3.1煅燒溫度對納米ZnO光催化性能的影響 22

3.3.2納米ZnO的投加量對其光催化性能的影響 24

3.4本章小結 25

第四章 結論 26

參考文獻 27

致謝 30