臺灣博碩士論文加值系統

本實驗在討論以鈦(Ⅳ)的烷氧化合物(alkoxide)經由溶膠-凝膠(Sol-Gel)法，製備納米(nano)級的二氧化鈦光觸媒粉體(powder)，有別於一般製備二氧化鈦的溶膠-凝膠過程，本實驗利用乙酸和丁酯經由酯化反應產生的水，與鈦的烷氧化合物進行水解反應，由於乙酸具有螯合物(chelating agent)的功能，因此可以降低醇氧化合物的高水解速度，避免快速沈澱的產生可以製備出均勻(homogeneous)相的二氧化鈦溶膠。經由氣相層析/質譜儀(GC/Mass)分析，乙酸丁酯的生成證實了酯化反應的發生。溶膠的FT-IR分析也證實乙酸在反應中扮演螯合物的角色。在經過500℃的鍛燒之後，可以得到晶相為anatase的二氧化鈦光觸媒。再利用Sol-Gel製程中加入適量的氯化銅(CuCl2)或氫六氯鉑酸(H2PtCl6‧xH2O)，通以氮氫混合氣在400℃還原3小時，得到不同金屬含量之還原形式之Cu/TiO2或Pt/TiO2光觸媒。
TEM顯示出Sol-Gel所製備出的顆粒大小約在15-25nm；XRD證實為anatase晶型之TiO2；UV-Vis的測量發現在Cu/TiO2有藍位移的現象，導致有較高的band gap energy；XPS之測量，發現Cu/TiO2的Ti(2p)有向高束縛能位移的現象，顯示Cu有捕捉電子的能力；Pt/TiO2的Ti(2p)則有向低束縛能位移的現象，顯示Pt與Ti存在著strong metal support interaction(SMSI)；BET測量出Sol-Gel所製備的TiO2之表面積約在30-70 m2/g，較商用TiO2大四倍，孔洞大小約在30-80A之範圍。

The objective of this study is to synthesize nano-particle titanium dioxide catalyst using Ti alkoxide via sol-gel route. Unlike the traditional technique, the hydrolyzing water is provided by the esterification of butanol and acetic acid. In addition, acetic acid also serves as chelating agent to stabilize the hydrolysis-condensation process and to avoid fast precipitation so that we could produce homo-geneous titanium dioxide sol. Esterification was verified by the product, butyl acetate, determined by a GC/Mass. The chelating complex was evidenced from FT-IR spectrum. After calcination at 500oC, anatase form titanium dioxide catalyst was obtained. Using Sol-Gel process, we also added some CuCl2 or H2PtCl6‧xH2O in TiO2 sol, and the products was reduced by H2 at 400oC for 3 hours. Then, Cu/TiO2 and Pt/TiO2 were prepared in reductive form with different metal content.
TEM showed catalyst particles size via sol-gel process were about 15-25nm; XRD spectra indicated anatase form TiO2; In UV-Vis analysis, it was found that Cu/TiO2 had a blue shift effect, resulting in higher band gap energy; From XPS measurement, it was found that the Ti(2p) of Cu/TiO2 shifted to higher binding energy, and was suggested that Cu had an ability to catch electrons; But the Ti(2p) of Pt/TiO2 shifted to lower binding energy, we suggested that Pt and Ti had strong metal support interaction(SMSI); By BET measurement, sol-gel derived TiO2 had surface area four times higher than that of Merck TiO2. Their surface area was about 30-70 m2/g, and pore size was in the range of 30-80A.

第一章 緒論 1
第二章 文獻回顧 2
2-1 二氧化鈦的製備方法 2
2-1-1 傳統製程 2
2-1-1-1 氯化法(chloride process) 2
2-1-1-2 溶凝膠法(Sol-Gel process) 2
2-2 pH值對溶凝膠的影響 7
2-3 溶劑的影響 7
2-4 觸媒簡介 10
2-4-1 二氧化鈦 10
2-4-2 負載金屬原子之二氧化鈦 13
2-4-3 二氧化鈦之顆粒量子效應(particle quantization
effect) 16
第三章 實驗內容 18
3-1 反應基本原理 18
3-2 藥品 21
3-3 實驗設備與儀器 21
3-4 實驗步驟 22
3-4-1 TiO2溶膠製備 22
3-4-2 Cu/TiO2溶膠製備 23
3-4-3 Pt/TiO2溶膠製備 23
3-4-4 溶膠之乾燥與煆燒 24
3-4-5 Cu/TiO2及Pt/TiO2觸媒之還原 24
3-4-6 氣相層析-質譜分析(GC-Mass) 28
3-4-7 傅利葉轉換紅外線光譜(FT-IR)分析 28
3-4-8 熱重及熱差分析(TGA/DTA) 28
3-4-9 氮氣吸附-脫附測定孔徑分佈與表面積 28
3-4-10 X-ray繞射法(XRD) 30
3-4-11 穿透式電子顯微鏡(TEM) 31
3-4-12 紫外-可見光光譜儀(UV-Vis Spectrophotometer) 31
3-4-13 化學分析電子能譜儀(Electron Spectroscopy for
Chemical Analysis，簡稱ESCA or XPS) 32
3-4-14 感應偶合電漿光譜(Inductively-Coupled Plasma
Spectrometor，簡稱ICP) 33
3-4-15 原子吸收光譜(Atomic Absorption Spectrometry,AA) 33
3-4-16 界面電位儀(Zeta Potential Measurements) 34
第四章 結果與討論 36
4-1 乙酸量之影響 36
4-2 GC-Mass分析 37
4-3 FT-IR分析 38
4-4 TGA/DTA分析 40
4-5 氮氣吸附法測量孔徑分佈 42
4-6 XRD分析 45
4-7 UV-Vis分析 57
4-8 TEM與電子繞射圖 63
4-9 XPS分析 68
4-10 表面電位(zeta potential)的測定 79
第五章 結論 80
參考文獻 82
第六章 附錄 87
表目錄
表2-1 Stretching vibrations of acetate ligands in different
Ti(Ⅳ)-Acetate complexes 6
表2-2 Charge distribution (δ) of partial-hydrolysis polymer
clusters of titanium alkoxide 9
表4-1 乙酸量與溶膠狀態 36
表4-2 觸媒之孔徑及表面積大小 42
表4-3 半高寬估算顆粒大小 49
表4-4 The JCPDS databases of anatase phase of TiO2 50
表4-5 The JCPDS databases of rutile phase of TiO2 51
表4-6 The JCPDS databases of Copper 55
表4-7 The JCPDS databases of Platinum 56
表4-8 觸媒之band edge value及band gap 58
圖目錄
圖2-1 酸性觸媒之親電子取代反應 5
圖2-2 乙酸鍵結於金屬之形式 6
圖2-3 乙酸和alkoxo group的兩種可能反應機構 7
圖2-4 矽之醇氧化合物加酸加鹼的反應 9
圖2-5 TiO6八面體 11
圖2-6 (a) anatase (b) rutile 結構圖 11
圖2-7 array of TiO6 octahedron for (a)anatase,(b)rutile 12
圖2-8 Cu/TiO2之反應機構圖 15
圖2-9 MO mode for particle growth for N monomeric units
The space of the energy levels (i.e.,density state) varies
among systems 16
圖2-10 Effective band gap of rutile TiO2 as a function of particle diameter 17
圖3-1 乙酸與Ti(OC4H9)4反應(a)chelating form (b)bridging form 19
圖3-2 TiO2溶膠之pH value 隨時間之變化 23
圖3-3(a) 實驗流程圖 25
圖3-3(b) 實驗流程圖 26
圖3-4 還原反應裝置圖 27
圖3-5 Cu含量之校正曲線 33
圖3-6 Pt含量之校正曲線 34
圖3-7 介面電位示意圖 35
圖4-1 二氧化鈦溶膠GC-Mass分析結果 37
圖4-2 二氧化鈦溶膠之FT-IR spectrum 38
圖4-3 Merck TiO2之FT-IR spectrum 39
圖4-4 TiO2-500℃之FT-IR spectrum 39
圖4-5 TiO2溶膠之TGA/DTA分析結果 40
圖4-6 Cu/TiO2溶膠之TGA/DTA分析結果 41
圖4-7 Pt/TiO2溶膠之TGA/DTA分析結果 41
圖4-8 TiO2-500℃累積孔洞體積vs.孔徑圖 43
圖4-9 TiO2-500℃之孔徑分佈圖 43
圖4-10 5.65wt% Cu/TiO2之孔徑分佈圖 44
圖4-11 0.1wt% Pt/TiO2之孔徑分佈圖 44
圖4-12 TiO2-500℃之XRD分析 45
圖4-13 TiO2-600℃之XRD分析 46
圖4-14 TiO2-700℃及TiO2-800℃之XRD分析比較 47
圖4-15 不同Cu含量之Cu/TiO2之 XRD分析比較 52
圖4-16 不同Pt含量之Pt/TiO2之XRD分析比較 53
圖4-17 1.3wt% Pt/TiO2之XRD分析 54
圖4-18 不同煆燒溫度TiO2之UV-Vis spectra 59
圖4-19 Cu/TiO2與TiO2之UV-Vis spectra比較 60
圖4-20 還原Pt/TiO2與TiO2之UV-Vis spectra比較 61
圖4-21 還原Pt/TiO2與未還原Pt/TiO2之UV-Vis spectra比較 62
圖4-22 TiO2-500℃ TEM micrograph 63
圖4-23 TiO2-700℃ TEM micrograph 64
圖4-24 TiO2-800℃ TEM micrograph 64
圖4-25 TiO2-500℃之電子繞射圖 65
圖4-26 10.8%wt Cu/TiO2-500℃ TEM micrograph 65
圖4-27 2.7%wt Cu/TiO2-500℃ TEM micrograph 66
圖4-28 1.5%wt Cu/TiO2-500℃ TEM micrograph 66
圖4-29 0.02%wt Pt/TiO2-500℃ TEM micrograph 67
圖4-30 0.1%wt Pt/TiO2-500℃ TEM micrograph 67
圖4-31 TiO2-500℃之Ti(2p) XPS spectra 70
圖4-32 TiO2-500℃之O (1s)XPS spectra 71
圖4-33 TiO2與Cu/TiO2之Ti(2p) XPS spectra比較 72
圖4-34 Cu/TiO2之O (1s)XPS spectra 73
圖4-35 Cu(2p3/2)之XPS spectra 74
圖4-36 TiO2與還原Pt/TiO2之Ti(2p) XPS spectra比較 75
圖4-37 TiO2與還原Pt/TiO2之O(1s) XPS spectra比較 76
圖4-38 TiO2與還原/未還原之Pt/TiO2之Ti(2p) XPS spectra比較 77
圖4-39 還原與未還原之Pt/TiO2之Pt(4f) XPS spectra比較 78
圖4-40 觸媒之表面電位圖 79
圖6-1 merck TiO2之孔徑分佈圖 87
圖6-2 TiO2-500℃之孔徑分佈圖 87
圖6-3 1.5wt% Cu/TiO2之孔徑分佈圖 88
圖6-4 11.2wt% Cu/ TiO2之孔徑分佈圖 88
圖6-5 0.02wt% Pt/ TiO2之孔徑分佈圖 89
圖6-6 0.3wt% Pt/ TiO2之孔徑分佈圖 89
圖6-7 以含浸法製備之TiO2與以溶凝膠法製備之TiO2產率 90
比較(包覆鋁箔紙反應)
圖6-8 還原與否對Pt/TiO2之產率影響(包覆鋁箔紙反應) 91

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