臺灣博碩士論文加值系統

本實驗以溶膠-凝膠法製備二氧化鈦光觸媒。首先將含有四乙基氧鈦之醇溶液滴入去離子水中，接著在90oC下進行迴流三小時。利用硝酸與氨水調整實驗中之pH值，所製得之粉體經過90oC乾燥後再進行不同溫度之煅燒。經由煅燒所得之粉體藉由XRD、DSC、TG、IR、BET、SEM及TEM做性質分析。而粉體之光活性測試則是分別在365nm紫外光燈及螢光燈管照射下，量測其對亞甲基藍的分解效率。結果顯示硝酸可能與四乙基氧鈦進行化學反應，導致煅燒後之二氧化鈦在結構上產生缺憾。此結構上的缺憾延緩了二氧化鈦由銳鈦礦轉變為金紅石。而pH值的改變影響了粉體的結晶度、相轉變及燒結溫度。在pH=7時，單一銳鈦礦相態可以維持在900oC。而pH=8及800oC煅燒後的粉體無論在365nm紫外光或螢光燈管的照射下，對於分解亞基藍擁有最佳的表現。

TiO2 photocatalysts were prepared using a sol-gel method. Alcoholic solution of tetraethylorthotitanite was dropped into de-ionized water, followed by refluxing the liquid at 90 oC for 3 hr. The pH of liquid was adjusted using HNO3 and NH4OH. The obtained particles were dried at 90 oC and calcined at different temperatures. The resultant calcined particles were characterized using XRD, DSC, TG, IR, BET, SEM, and TEM. Photoactivity of the obtained particles was investigated by degrading methylene blue under illumination of 365nm UV and fluorescent light. The results indicated that HNO3 may react with tetraethylorthotitanite and result in the formation of structure defects in TiO2 after calcination. These structure defects retarded phase transformation of anatase to rutile. Effects of pH on crystallinity, phase transformation and sintering temperature were investigated. At pH = 7, anatase nanoparticles can be retained at temperatures as high as 900 oC without transforming to rutile phase. The specimen obtained at pH = 8 and at 800 oC showed the highest photoactivity on degrading methylene blue under either 365nm UV or fluorescent light illumination.

CONTENS OF FIGURES III
CONTENS OF TABLES IX
CHAPTER 1 INTRODUCTION 1
CHAPTER 2 LITERATURE REVIEW 3
2-1 Titanium Dioxide 3
2-2 Preparation of Titanium Dioxide 9
2-2-1 Sol-Gel Method 9
2-2-2 Microemulsion Method 11
2-2-3 Metallorganic Chemical Vapor Deposition 11
2-3 Improvements of Photoability 13
2-3-1 Doping Metallic Ions 13
2-3-2 Coupled photocatalysts 16
2-3-3 Dye sensitized photocatalysts 17
2-4 Quantum Size Effect 18
CHAPTER 3 EXPERIMENTAL TECHNIQUES 20
3-1 Experimental 20
3-1-1 Pure TiO2 20
3-1-1 Undoped TiO2 20
3-1-3 TiO2 doped with vanadium 21
3-2 Characteristic Analyses 24
3-2-1 X-ray Diffraction 24
3-2-2 Electron Microscopy 25
3-2-3 Infrared Spectroscopy 25
3-2-4 Thermal Analyses 26
3-2-5 BET Analysis 27
3-3 Photocatalytic Analysis 28
3-3-1 Methylene Blue 28
3-3-2 Design of Photocatalysis 28
CHAPTER 4 RESULTS AND DISCUSSION 31
4-1 Comparisons with Pure TiO2 and Commercial P25 31
4-2 Undoped TiO2 without adjusting pH 39
4-3 Undoped TiO2 with adjusting pH 46
4-4 Doped TiO2 with vanadium at pH=7 75
CHAPTER 5 CONCLUSIONS 80
REFERENCES 81

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