本篇論文主要探討氧化鋅/氧化亞銅所組成的第二型半導體異質結構進行光催化還原二氧化碳的表現之研究。本實驗選用兩種預期有不同光催化活性的氧化亞銅結構，分別為（100）面的立方體(cube)氧化亞銅與（110）面的菱形十二面體(rhombic dodecahedron, r.d.)氧化亞銅，並利用近室壓光電子光譜術（APXPS）對光催化劑表面上反應物種的變化進行表徵。我們準備了一系列樣品，例如ZnO (7％)/ Cu2O (cube)、ZnO (7％)/ Cu2O (r.d.)、ZnO (20％)/ Cu2O (r.d.)以及ZnO (40％)/ Cu2O (r.d.)。由APXPS C 1s光譜顯示出在菱形十二面體氧化亞銅系列的樣品表面上生成了大量碳中間體（例如甲酸酯，羰基和甲氧基），這證明了ZnO / Cu2O（r.d）比ZnO / Cu2O (cube)更具反應活性。此外，在Cu2O (r.d.)的系統中，相較於低氧化鋅負載量(7%)的產物以甲醇為主，數據顯示當提高ZnO的負載量(40%)會導致生成甲烷的比例提高。我們使用APXPS的數據建構出與光催化劑表現相關的能帶圖，經由計算後，與ZnO / Cu2O (cube)系統的數值相比，發現ZnO/Cu2O (r.d.)系統中，氧化亞銅與氧化鋅的價帶位能差(conduction band offset, ∆ECBO)與導帶位能差(valence band offset, ∆EVBO)皆來的大，但氧化亞銅的價帶與氧化鋅的導帶之間的能量差卻比較小，此因素導致光電子電洞對有更高機率的在此兩能階中再結合，讓氧化亞銅的導帶累積更多的光激發電子幫助催化反應；亦有可能是在ZnO / Cu2O (cube)系統中異質接面產生時氧化亞銅價帶下彎過多，造成電子傳遞能力下降。

In this thesis, we report a photocatalytic reduction study of carbon dioxide on semiconductor heterojunctions constructed from nanoparticles of cuprous oxide and zinc oxide with cuprous oxide of two different facets. The samples investigated include ZnO (7%)/ Cu2O (cube), ZnO (7%)/ Cu2O (r.d.) and ZnO (40%)/ Cu2O (r.d.). Two types of cuprous oxide nano-crystals were selected based on the anticipated difference in photocatalytic performance: the cubic structure terminated with (100) faces, and the rhombic dodecahedron (r.d.) terminated with (110) faces. Ambient pressure X-ray photoelectron spectroscopy (APXPS) was used to track the change of reaction species on the photocatalyst surfaces. The ZnO/Cu2O (r.d.) is found to be more reactive than ZnO/Cu2O (cube) as evidenced by a larger production of carbon species such as carbonate, formate, carbonyl, and methoxy on the surface when the nano-catalysts were exposed to gaseous carbon dioxide and water of mbar pressure and illuminated with UV photons. Further, increasing ZnO loading from 7% to 40%, on Cu2O (r.d.) alters reaction pathway, yielding more methane instead of methanol. The energy diagrams useful in discerning the catalytic performance of photocatalysts are also constructed by means of APXPS data. The semiconductor interfaces of ZnO/Cu2O (r.d.) and ZnO/ Cu2O (cube) are all belonged to type II heterojunction. The valence band maximum (VBM) of Cu2O (r.d.) is found to be located at 1.28 eV lower than the conduction band minimum (CBM) of ZnO, whereas the corresponding energy level difference for ZnO/ Cu2O (cube) is increased to 1.83 eV. We speculated that the smaller energy difference brings about a faster interfacial recombination rate between the holes residing in VBM of Cu2O (r.d.) and electrons residing in CBM of ZnO when the materials are illuminated with UV photos, resulting in an improved charge separation with electrons accumulated at Cu2O (r.d.) and holes at ZnO, as depicted in the so-called Z-scheme.

目錄
摘要 i
Abstract iii
圖目錄 viii
表目錄 xiii
第 1 章 前言 1
1-1研究背景 1
第 2 章 文獻回顧 3
2-1光催化反應(photocatalytic reaction) 3
2-2異質接面光催化材料(heterojunction photocatalyst) 4
2-3異質接面半導體之光反應機制 6
2-4奈米材料的晶面效應(facet effect) 9
2-5晶面效應對異質接面的催化影響 10
2-6二氧化碳光還原反應機制 13
第 3 章 實驗技術與原理介紹 19
3-1同步輻射光源 19
3-2 X光光電子能譜術 (X-ray Photoelectron Spectroscopy, XPS) 21
3-2-1 X-ray激發原子內電子之反應機制 21
3-2-2 X光光電子能譜術(X-ray photoelectron spectroscopy) 22
3-2-3束縛能與化學位移 25
3-2-3-1 Koopmans’ theorem 25
分析XPS的數據時，分析儀收集到的是光電子剩餘的電子動能，而我們將其轉換成束縛能來探討，由Einstein equation可得知: 25
3-2-3-2初狀態效應(Initial effect) 27
3-2-3-3末狀態效應(final effect) 30
3-3 近室壓X光光電子能譜術 (Ambient Pressure XPS, APXPS) 31
3-4 質譜儀 36
第 4 章 實驗藥品、儀器設備與實驗步驟 39
4-1實驗藥品與儀器 39
4-2實驗樣品製備 41
4-2-1 氧化亞銅奈米材料製備 41
4-2-2 氧化亞銅-氧化鋅奈米材料製備 43
4-2-3 樣品導入腔體步驟 44
4-3 TLS BL24A 近室壓 X 光光電子能譜實驗站 44
4-3-1 室壓光電子能譜系統(AP-XPS) 44
4-3-2 進樣系統 46
4-4 實驗步驟 47
第 5 章 實驗結果與討論 49
5-1 實驗設計 49
5-2 樣品鑑定 50
5-3 材料表面清潔 53
5-4 室壓光電子光譜數據分析 57
5-4-1 相關文獻回顧 58
5-4-2 光譜分析 61
5-4-2-1 ZnO (7%)/ Cu2O (r.d.) 61
5-4-2-2 ZnO (7%)/ Cu2O (cube) 69
5-4-2-3 ZnO (20%)/ Cu2O (r.d.) 74
5-4-2-4 ZnO (40%)/ Cu2O (r.d.) 80
5-6能帶測量與計算 85
5-7 質譜數據分析 92
5-8 綜合討論 95
第 6 章 結論 98
第 7 章 引用文獻 100
 
圖目錄
圖 1 1. 自十八世紀開始全球的平均溫度變化2 2
圖 1 2. 二氧化碳濃度變化圖，於2019/05/14首度觀測到濃度突破415ppm3 2
圖 2 1. 常見半導體材料之能隙圖9 5
圖 2 2. (a)第一型 (b) 第二型(c) 第三型異質結構 6
圖 2 3. 第二型異質接面受光激發後電子可能的反應路徑9，(a) Double charge transfer mechanism (b) Z-scheme mechanism 7
圖 2 4. α-Fe2O3/Cu2O受光激發後電子移動路徑10 8
圖 2 5. 氧化亞銅-二氧化鈦(左)與氧化亞銅(右)奈米材料受光激發後反應路徑6 9
圖 2 6. 不同晶面氧化亞銅對甲基橙之降解效率圖11 10
圖 2 7. 氧化亞銅晶面示意圖，黃圈帶表末端銅原子11 10
圖 2 8. 不同晶面的氧化亞銅-硫化鋅奈米材料對甲基橙降解效率圖 11
圖 2 9. (a)不同晶面之氧化亞銅-硫化鋅能帶圖(b)cube (c)RD (d)Octahedron 12
圖 2 10. 理論計算之不同晶面氧化亞銅與硫化鋅能帶圖 12
圖 2 11. 直線與彎曲型二氧化碳之分子軌域 15
圖 2 12. 二氧化碳還原至甲烷之反應途徑示意圖17 18
圖 3 1. 同步輻射環內電子束運行示意圖 20
圖 3 2. 同步加速器光源產生示意圖 20
圖 3 3. 元素受X光激發後電子移動路徑圖 21
圖 3 4. XPS原理示意圖 22
圖 3 5. 利用XPS判斷材料內含之元素種類 23
圖 3 6. 電子的平均自由徑與其動能之關係圖18 24
圖 3 7. 不同能量對應之深度示意圖 24
圖 3 8. 導體樣品與分析儀能階示意圖 26
圖 3 9. (a)無機硫化物的硫1s化學位移與氧化態關係圖(b)硫2p理論計算之電荷對束縛能關係圖 27
圖 3 10. 處在不同化學環境的C 1s之束縛能列表 28
圖 3 11. 自旋軌道分裂示意圖 29
圖 3 12. Au 4f XPS圖譜 29
圖 3 13. (a)不同價數之銅2p XPS圖 (b)Cu Auger LVV圖譜 31
圖 3 14. (a)傳統超高真空X光光電子能譜；(b)近室壓X光光電子能譜儀之系統架構示意圖 32
圖 3 15. 電磁透鏡聚焦電子示意圖19 33
圖 3 16. 鄰近壓差比抽氣系統入口之壓力分佈圖 (p為局部位置壓力；po為腔體之背景壓力)20 34
圖 3 17. 不同厚度的氮化矽對X光的穿透率比較圖 35
圖 3 18. 質譜儀組成示意圖21 37
圖 3 19. 四極柱質量分析器示意圖22 38
圖 3 20. 光電倍增管示意圖23 38
圖 4 1. 立方體氧化亞銅奈米粒子合成步驟圖 42
圖 4 2. 菱形十二面體氧化亞銅奈米粒子合成步驟圖 43
圖 4 3. 氧化亞銅-氧化鋅奈米粒子合成步驟圖 44
圖 4 4. 氣體歧管系統 46
圖 5 1. Cu2O (cube)之SEM圖 50
圖 5 2. ZnO (7%)/ Cu2O (cube)之SEM圖 51
圖 5 3. Cu2O (r.d.)之SEM圖 51
圖 5 4. ZnO (7%)/ Cu2O (r.d.)之SEM圖 52
圖 5 5 . (左)ZnO (20%)/ Cu2O (r.d.)(右) ZnO (40%)/ Cu2O (r.d.)之SEM圖 52
圖 5 6. 清潔ZnO/Cu2O (r.d.)表面過程前後之(左)C 1s圖譜(右)全譜變化 54
圖 5 7. 清潔ZnO/Cu2O (cube)表面過程前後之(左)全譜(右) C 1s圖譜變化 54
圖 5 8. (左)氬氣濺鍍後之氧化鋅-氧化亞銅奈米粒子之Cu Auger LMM光譜。(右)金屬銅、氧化亞銅及氧化銅之Cu LMM參考圖24-25。 56
圖 5 9. 氫氣濺鍍表面30分鐘之Cu LMM光譜 56
圖 5 10. (左)氧化鋅-氧化亞銅奈米粒子之Cu L-edge光譜(右)金屬銅、氧化亞銅及氧化銅之Cu L-edge參考圖26 57
圖 5 11. 373K下曝入0.8 mbar CO2至活性較高的Zn(0.32ML)-Cu(111)量測之(a)C 1s (b)O 1s 光譜28 59
圖 5 12. ZnO (7%)/ Cu2O (r.d.)之APXPS C 1s圖譜, 入射光能量為750 eV 61
圖 5 13. ZnO (7%)/ Cu2O (r.d.)照光前後材料表面物比例圖 64
圖 5 14. ZnO (7%)/ Cu2O (r.d.)之APXPS O 1s圖譜，入射光能量為700 eV 66
圖 5 15. ZnO/Cu2O (cube)之APXPS C 1s圖譜，入射光能量為750 eV 69
圖 5 16. ZnO (7%)/ Cu2O (cube)之APXPS O 1s圖譜，入射光能量為700 eV 72
圖 5 17. ZnO (20%)/ Cu2O (r.d.)之APXPS C 1s圖譜，入射光能量為450 eV 74
圖 5 18. ZnO (20%)/ Cu2O (r.d.)照光前後材料表面物種比例圖 76
圖 5 19. ZnO (20%)/ Cu2O (r.d.)之APXPS O 1s圖譜，入射光能量為700 eV 78
圖 5 20. ZnO (40%)/ Cu2O (r.d.)之APXPS C 1s圖譜，入射光能量為450 eV 80
圖 5 21. ZnO (40%)/ Cu2O (r.d.)照光前後材料表面物比例圖 82
圖 5 22. ZnO (40%)/ Cu2O (r.d.)之APXPS O 1s圖譜，入射光能量為700 eV 84
圖 5 23. Cu2O (r.d.)之XPS Cu 3p及VB圖 86
圖 5 24. Cu2O (cube)之XPS Cu 3p及VB圖 86
圖 5 25. ZnO之XPS Zn 3p及VBM圖 87
圖 5 26. ZnO/Cu2O (r.d.)異質接面之XPS Cu 3p及Zn 3p圖 87
圖 5 27. ZnO/Cu2O (cube) 異質接面之XPS Cu 3p及Zn 3p圖 88
圖 5 28. ZnS/Cu2O異質接面能帶圖43 89
圖 5 29. 兩不同半導體的異質接面處的能帶校準示意圖 90
圖 5 30. ZnO/Cu2O (r.d.)及ZnO/Cu2O (cube)能帶圖 92
圖 5 31. 程序升溫脫附實驗質譜圖(全譜) 94
圖 5 32. 程序升溫脫附實驗質譜圖(選區放大) 94
圖 5 33. 程序升溫脫附實驗質譜圖(荷質比=74) 95
 
表目錄
表 2 1. 二氧化碳光還原的常見產物及還原電位 13
表 2 2. 水接受電子或電洞之反應電位 16
表 4 1. 實驗藥品 39
表 4 2. 實驗儀器 40
表 5 1. 各樣品之氧化鋅重量百分比 49
表 5 2. ZnO (7%)/ Cu2O (r.d.) C 1s光譜fitting參數表 65
表 5 3. ZnO (7%)/ Cu2O (r.d.) O 1s光譜fitting參數表 68
表 5 4. ZnO (7%)/ Cu2O (cube) C 1s光譜fitting參數表 71
表 5 5. ZnO (7%)/ Cu2O (cube) O 1s光譜fitting參數表 73
表 5 6. ZnO (20%)/ Cu2O (r.d.) C 1s光譜fitting參數表 77
表 5 7. ZnO (20%)/ Cu2O (r.d.) O 1s光譜fitting參數表 79
表 5 8. ZnO (40%)/ Cu2O (r.d.) C 1s光譜fitting參數表 83
表 5 9. ZnO (40%)/ Cu2O (r.d.) O 1s光譜fitting參數表 85
表 5 10. 能譜參數一欄表 88
表 5 11. 能帶計算參數一欄表 91

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