二氧化鈦是當前最常用來應用於光電系統的材料之一，本研究使用三種製備方式合成二氧化鈦並量測其光電性質。第一個方法是微波輔助水熱法製備二氧化鈦摻雜二氧化釕(將其命名為2 mol% RT-x℃, x=300, 400, 500, 800)之奈米粉體；第二種方法是使用陽極處理法在鈦片基材上成長出一維二氧化鈦奈米管柱陣列，並且改變陽極處理電壓以合成不同形貌之管柱(x V-1 h, x=20, 40, 60, 80)；第三種製備法是在鈦片表面酸洗後，將樣品於高溫下鍛燒，改變不同鍛燒溫度並持溫兩個小時(命名為x℃-2 h, x=550, 600, 700, 800)與固定鍛燒溫度600℃並持溫於不同時間(命名為600℃-x h, x=0.5, 2, 4, 6)以進行鍛燒。
以上述三種方式合成的二氧化鈦，其材料分析包括以X光繞射分析鑑定樣品之晶相與粒徑大小；以掃描式電子顯微鏡分析樣品表面形貌。光電化學性質測試包含AM1.5G模擬太陽光光照下之開環路電位測量和以線性掃描伏安法測量五秒開關燈之光電流應答；另外，本研究使用循環伏安法量測白金的氧氣還原極限電流(iL)。
經光電性質量測後，直接鍛燒法是三者之中光電流表現最佳之樣品，鍛燒溫度600℃持溫六小時之樣品(600℃-6 h)，其在所有條件中具有最負光電位Eph =-0.80 V vs. Ag/AgCl，並且有最高的光電流密度值i=323 μA cm−2 (at 1 V vs. RHE)。
本研究也提出計算光電轉換效率時所必須要注意的條件，若未使用正確條件則易產生效率值過高之後果。最常見的光電轉換效率計算公式為solar-to-hydrogen efficiency (STHE)與applied bias photon-to-current efficiency (ABPE)。最常見的計算是將半反應(工作電極)的電位代入公式中進行計算，但是全反應的電壓才是促使陰陽極真正發生反應的電壓。實驗方法是使用胡啟章教授實驗室特有的外接式監控盒，在線性掃描伏安法量測工作電極時，同時使用監控盒監控對電極的電位，並透過此方法將可以間接得到全反應電壓，再將此全反應電壓代入效率公式中進行計算。
此外，本研究亦開發淨功率值之計算方法，透過改變三個實驗變因以分析樣品600℃-6 h其淨功率值之差異：(1)改變光源-紫外光或是太陽光、(2)改變對電極白金絲之面積(Pt-0.2 cm與Pt-2 cm)以及(3)是否透過電流效率值η_F修正水還原的電流。這三個因素皆會造成產氫電位的改變，因而導致計算效率值時產生差異，若光電流密度值夠顯著(>1 mA cm−2)時，則η_F值變動小，而效率值在此情況下則差異不大；目前光電轉換效率值之研究之效率仍然低，因此本研究結果對於低光電效率之裝置提供一個準則以供參考。

TiO2 (anatase and rutile phase) is one of the most investigated materials for photoelectrochemical applications. In this work, TiO2 were fabricated by three methods: (1) ruthenium doped titanium dioxide (2 mol% RT-x℃, x=300, 400, 500, 800) was synthesized by the microwave-assisted hydrothermal (MAH) method, (2) 1D TiO2 nanotube arrays(x V-1 h, x=20, 40, 60, 80) were growned on Ti foils by the anodization method, and (3) direct calcination of Ti foils with various calcination temperatures (x℃-2 h, x=550, 600, 700, 800) and change of calcination durations (600℃-x h, x=0.5, 2, 4, 6).
The synthesized TiO2 were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to study their crystal phases and surface morphologies. Moreover, the TiO2’s photoelectrochemical behaviors such as photopotential and transient photocurrent response were studied via open circuit potential (OCP) function and linear sweep voltammetry (LSV) under AM 1.5G simulated solar light irradiation, respectively. Hydrogen adsorption/desorption on platinum electrodes were conducted with cyclic voltammetry (CV).
The third synthesizing method, direct calcination method, outperforms the former two methods in its photocurrent density, stability and the fabrication’s simplicity; therefore, samples fabricated by direct calcination method were used as the working electrodes in further photo-electrochemical studies. Direct calcination method is a simple and time-saving technique which successfully fabricates rutile phase titanium dioxide. By changing calcination temperatures and calcination time after surface cleaning with 6M HCl solution at 90℃ for 40 minutes, sample 600℃-6h was found to own the best PEC property with the most negative photopotential (Eph=-0.80 V vs. Ag/AgCl) and highest photocurrent density value(323 μA cm−2 at 1 V vs. RHE).
This work also addressed the importance of proper conditions when calculating PEC efficiencies such as solar-to-hydrogen efficiency (STHE) and applied bias photon-to-current efficiency (ABPE) in order to avoid overestimation of efficiencies. The cell voltages, which are required in the equations for efficiency calculations, were obtained using the potential’s monitoring system invented by Professor Chi-Chang Hu’s laboratory.
The last part of the PEC measurements were conducted by changing three parameters in LSV method: (1) light source (UV or sun light), (2) counter electrode’s (Pt) surface area (Pt-0.2 cm and Pt-2 cm), and (3) whether the residual oxygen existed in the electrolyte or not (N2 or w/o N2). These three parameters influence cell voltages and hence result in different efficiency values. Moreover, this work has modified the ABPE equation and created our own protocol, net power gained values, which could provide another route for the future researches when calculations of efficiency and net power gained values are required.

致謝 I
摘要 III
Abstract V
目錄 VII
圖目錄 XI
表目錄 XX
第一章 緒論及理論基礎 1
1-1緒論 1
1-2光電半導體原理與光電催化水分解原理 2
1-2-1光觸媒的基本原理 2
1-2-2光電半導體的基本原理 5
1-2-3光電半導體光電化學行為表現 6
1-2-4光電催化水分解及其效率值 10
1-3二氧化鈦的介紹 12
1-3-1二氧化鈦的物理與化學性質 12
1-3-2二氧化鈦的製備方法 15
1-3-3二氧化鈦應用於水分解之研究 22
1-4研究動機 26
第二章 實驗方法與儀器介紹 29
2-1儀器與藥品 29
2-1-1儀器 29
2-1-2藥品 31
2-2微波輔助水熱法及電極製備 33
2-2-1微波輔助水熱法實驗流程 33
2-2-2石墨電極製備 35
2-3陽極處理法及電極製備 36
2-3-1陽極處理法 36
2-3-2鈦片電極製備 37
2-4直接鍛燒氧化法與電極製備 38
2-4-1直接鍛燒法 38
2-4-2鈦片電極製備 38
2-5材料分析及原理簡介 40
2-5-1 X光繞射分析 (X-ray Diffraction Analysis, XRD) 40
2-5-2掃描式電子顯微鏡 (Scanning Electron Microscopy, SEM) 43
2-5-3線性掃描伏安法(Linear Sweep Voltammetry, LSV) 44
2-5-4循環伏安法(Cyclic Voltammetry, CV) 46
2-5-5光電轉換效率 (STHE and ABPE) 47
2-5-6開環路電位法 (OCP Decay Method) 48
2-5-7電化學監控對電極法 50
2-6實驗流程 51
第三章 微波輔助水熱法製備光陽極 52
3-1二氧化鈦摻雜二氧化釕之材料分析 53
3-1-1 X光繞射之分析 53
3-1-2掃描式電子顯微鏡之表面形貌分析 55
3-1-3 掃描式電子顯微鏡之能量散佈光譜儀 (EDS) 57
3-2線性掃描伏安法之光電流應答分析 59
3-3結果與討論 61
第四章 陽極處理法製備光陽極 62
4-1二氧化鈦奈米鈦管材料分析 64
4-1-1 X光繞射分析 64
4-1-2掃描式電子顯微鏡之表面形貌分析 66
4-2二氧化鈦奈米鈦管光電化學分析 69
4-2-1光電位測量 69
4-2-2線性掃描伏安法之光電流應答分析 71
4-3結果與討論 73
第五章 直接鍛燒法製備光陽極 74
5-1二氧化鈦薄膜材料分析 75
5-1-1 X光繞射分析 75
5-1-2掃描式電子顯微鏡之表面形貌分析 78
5-2二氧化鈦薄膜電化學行為分析 82
5-2-1光電位測量 82
5-2-2線性掃描伏安法之光電流應答分析 85
5-2-3電化學監控(對電極)法 88
5-3效率值與淨功率值 90
5-3-1 STHE與ABPE之比較 90
5-3-2氫氣於白金電極之吸脫附行為表現 93
5-3-3淨功率值之探討 97
5-4結果與討論 113
第六章 總結與未來展望 115
6-1總結 115
6-2未來展望 119
附錄 121
(I)陽極處理法管柱形成之機制 121
(i)陽極處理之電壓影響 121
(ii)陽極處理時間的影響 121
(iii)電解液對於奈米管柱的影響 122
(iv)熱處理之影響 123
(v)二氧化鈦奈米鈦管成長機制 124
(II)Diffuse Reflectance Spectroscopy (DRS) 128
(III)電化學監控對電極法 129
參考文獻 131

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