臺灣博碩士論文加值系統

本論文著重在探索廉價易取得且實用的光催化劑平台，以便在綠色能源與永續環境等循環經濟領域取得重大突破與應用。論文中主要以溶膠凝膠法與靜電紡絲法製備金屬氧化物半導體材料，作為光觸媒降解亞甲基藍或亞甲基橙染料。研究中使用了TiO2、ZnO、SnO2做為半導體材料觸媒，並透過摻雜貴金屬與混和形成異質結構半導體材料光觸媒來進行光降解測試評估。所有半導體材料以掃描式電子顯微鏡、穿透式電子顯微鏡、X光粉末繞射儀及X射線能量散布分析儀來分析其表面形貌、晶體結構及光學特性，同時對半導體材料之光催化效果進行測試。研究結果顯示，TiO2/ZnO此種異質結構半導體材料光觸媒具有最佳降解效率，當其混和莫爾比為0.75/0.25時，4小時內對亞甲基藍溶液有70%降解率，高於其他光觸媒材料的降解效果。而當此最佳混合比之TiO2/ZnO異質結構材料摻雜1 mole%銀時，其4小時之降解效率可有效提升13%增加至83%。

This thesis focuses on exploring an affordable, abundant, and effective photocatalyst to achieve major breakthroughs and applications in circular economy such as green energy and environmental sustainability. The metal-oxide semiconductor used in this study was prepared using the sol-gel process and electrospinning and was used as a photocatalyst to degrade methylene blue or methylene orange dyes.
Furthermore, TiO2, ZnO, and SnO2 were used as the semiconductor catalysts for photodegradation tests and assessments carried out by doping noble metals and hybridization and forming heterostructure semiconductor photocatalysts. All of the semiconductors were analyzed using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy for their surface morphology, crystal structure, and optical properties, and their photocatalytic rates were estimated.
The research results showed that the TiO2/ZnO heterostructure semiconductor photocatalyst had the best degradation efficiency. When the mixing molar ratio was 0.75/0.25, the degradation rate of the methylene blue solution was 70% within four hours, which was higher than that of other photocatalysts. Moreover, when the TiO2/ZnO heterostructure material with the optimal mixing ratio was doped with 1 mole% silver, its four-hour degradation efficiency could be increased by 13% to 83%.

Contents
摘 要 ............................................................................................................................. i
Abstract ........................................................................................................................... ii
誌謝 ........................................................................................................................... iii
Contents........................................................................................................................... v
List of table captions ................................................................................................... viii
List of figure captions.................................................................................................... ix
Chapter 1 Introduction .................................................................................................. 1
1.1 Background ....................................................................................................... 1
1.2 Motivation ......................................................................................................... 3
1.3 Thesis organization........................................................................................... 5
Chapter 2 Literature review.......................................................................................... 6
2.1 Introduction to TiO2 ......................................................................................... 6
2.2 Introduction to ZnO......................................................................................... 8
2.3 Introduction to SnO2 ...................................................................................... 10
2.4 Photocatalysts ..................................................................................................11
2.4.1 Background Information .....................................................................11
2.4.2 Photocatalysis Theory ......................................................................... 13
2.4.3 Photocatalysis Process......................................................................... 15
2.5 Semiconductor Photocatalyst Variations...................................................... 17
2.6 Semiconductor Photocatalyst Modifications................................................ 19
vi
2.6.1 Compound Semiconductor Materials................................................ 19
2.6.2 Doping Elements.................................................................................. 19
2.6.2.1 Doping Non-metallic Ions ............................................................ 19
2.6.2.2 Doping Metallic Ions .................................................................... 20
2.7 Electrospinning technique ............................................................................. 20
2.7.1 Influence Coefficient of Electrospinning.......................................... 21
2.8 Sol-Gel method................................................................................................ 23
2.9 Quantum size effect ........................................................................................ 29
Chapter 3 Materials and method ................................................................................ 30
3.1 Materials.......................................................................................................... 30
3.2 Experimental procedure ................................................................................ 30
3.2.1 Preparation of ZnO nanopowders using sol-gel process...................... 30
3.2.2 Preparation of TiO2 and Ag/TiO2 nanofibers using electrospinning process............................................................................................................ 31
3.2.3 Preparation of SnO2 nanopowders using sol-gel process..................... 31
3.2.4 Preparation of the ZnO/SnO2 heterostructure nanocatalysts ............. 32
3.2.5 Preparation of the TiO2/ZnO heterostructure nanocatalysts .............. 32
3.3 Measurement and analysis............................................................................. 33
3.4 Photocatalytic activity measurements .......................................................... 33
Chapter 4 Results and Discussion ............................................................................... 35
4.1 Photocatalytic and optical characteristics of SnO2 and SnO2/ZnO catalysts ........................................................................................................................ 35
4.2 Structural, optical characterization and photocatalytic behavior of Ag/TiO2
vii
nanofibers...................................................................................................... 42
4.3 Characteristics and heterostructure of metal-doped TiO2/ZnO nanocatalysts ................................................................................................. 50
Chapter 5 Conclusions ................................................................................................. 67
Acknowledgements ....................................................................................................... 68
References...................................................................................................................... 69
Curriculum vitae .......................................................................................................... 75
Publication list .............................................................................................................. 76

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