臺灣博碩士論文加值系統

本研究以擔載氧化鎵之奈米碳管(Ga/CNTs)為模板，並以蒸氣輔助結晶法(steam-assisted crystallization，SAC)合成多級孔的Ga/ZSM-5，並與含浸法製備的Ga/ZSM-5及多級孔Ga/ZSM-5進行比較，探討介孔和不同擔載鎵的方式對甲醇芳香化的影響。結果顯示，以CNTs(或Ga/CNTs)為模板所衍生的介孔構造可降低反應物和產物於微孔內的質傳阻力，進而提升芳香族的產率和延長觸媒的壽期。然而，以Ga/CNTs為模板所合成的Ga/ZSM-5，不僅能生成介孔，亦具有良好的鎵分散性及脫氫活性，其原因為較多的(GaO)+能和布朗斯特酸之間行協同效應(Synergetic effect)進而促進甲醇芳香化，於500 oC下的芳香族產率達73%，遠高於其他方式所合成的ZSM-5的產率。一系列的觸媒物化性鑑定，如XRD、BET、SEM、TEM、NMR、ICP、NH3-TPD、H2-TPR、Pyridine-IR、MeOH-TPSR等，將在本論文中探討。

Hierarchical Ga/ZSM-5 catalysts were synthesized by using a one-pot process of
combined hard-templating and steam-assisted conversion. Compared with Ga-incorporated ZSM-5 made by impregnation and by sequential CNTs templating and impregnation, hierarchical Ga/ZSM-5 had a moderate mesoporosity and possibly a high concentration of (GaO)+-Brønsted acid site. The mesoporosity could reduce the mass transfer resistance of products in the porosity. Moreover, the synergy effect between (GaO)+-Brønsted acid site enhances the aromatization activity.Among prepared catalysts, hierarchical Ga/ZSM-5 was the most effective catalyst in methanol aromatization. The aromatics yield of 72.6% was achieved in MTA at 500 oC. All the prepared catalysts were characterized using various techniques including XRD, nitrogen adsorption–desorption, SEM, TEM, NMR, ICP, NH3-TPD, H2-TPR, Pyridine-IR, MeOH-TPSR, TGA.

目錄

摘要 I
英文延伸摘要 II
誌謝 VIII
表目錄 XII
圖目錄 XIII
第一章 前言 1
第二章 文獻回顧 3
2.1沸石觸媒特性 3
2.2甲醇轉化為芳香族之反應機制 8
2.3沸石觸媒改質之研究 14
第三章 實驗 19
3.1 X光繞射儀(XRD) 19
3.2比表面積及孔徑分析儀 21
3.3高解析度穿透式電子顯微鏡(HR-TEM) 23
3.4高解析度掃描式電子顯微鏡(HR-SEM) 24
3.5感應耦合電漿質譜分析儀(ICP-MS) 25
3.6固態核磁共振儀(NMR) 26
3.7自動式化學吸脫附儀 28
3.7.1氨氣程序升溫脫附(NH3-TPD) 29
3.7.2異丙胺程序升溫脫附(Isopropylamine-TPD) 30
3.7.3氫氣程序升溫還原(H2-TPR) 32
3.7.4程序升溫表面反應(TPSR) 32
3.8紅外線吸收光譜(FTIR) 39
3.8.1觸媒之紅外線吸收光譜 40
3.8.2吡啶吸附之紅外線吸收光譜(Py-IR) 40
3.9 X光光電子能譜(XPS) 43
3.10熱重分析儀(TGA) 45
3.11氣相層析儀(GC) 46
3.12產物定性與定量分析 48
3.13藥品與實驗設備 51
3.14觸媒的合成及製備 54
3.14.1 ZSM-5製備 54
3.14.2以Ga/CNTs為模板的多級孔Ga/ZSM-5和以CNTs為模板的多級孔ZSM-5之製備 54
3.14.3 Ga/ZSM-5和多級孔的Ga/ZSM-5之觸媒製備 55
3.15觸媒MTA反應性及壽期測試 56
第四章 結果與討論 57
4.1物理性質鑑定 57
4.1.1奈米碳管(CNTs)之熱重分析 57
4.1.2 Ga/CNTs之氫氣程溫還原 58
4.1.3觸媒組成分析(ICP-AES) 59
4.1.4觸媒之XRD鑑定 59
4.1.5觸媒的表面形貌鑑定(SEM和TEM) 60
4.1.6觸媒氮氣等溫吸附及脫附曲線 64
4.1.7觸媒27Al NMR鑑定結果 67
4.1.8觸媒29Si NMR鑑定結果 68
4.1.9觸媒之紅外線光譜 69
4.2 化學性質鑑定 70
4.2.1觸媒氫氣程溫還原(H2-TPR) 70
4.2.2觸媒氨氣與異丙胺程溫脫附 (NH3-TPD ＆ IPA-TPD) 71
4.2.3吸附吡啶觸媒之紅外光譜(Pyridine-IR) 75
4.2.4觸媒之Ga 2p軌域X射線光電子能譜(XPS) 77
4.2.5甲醇程溫表面反應(MeOH-TPSR) 78
4.2.6觸媒於甲醇轉化為芳香族之反應性結果 81
4.2.7觸媒壽期測試及積碳 85
第五章 結論 88
第六章 未來方向 89
參考資料 90

 
表目錄
表2- 1 沸石觸媒之相關反應途徑 7
表2- 2甲醇轉化觸媒與其操作條件和反應性之比較 10
表2- 3 改質ZSM-5於MTA反應研究結果 18
表3- 1實驗藥品與材料 51
表3- 2實驗設備之名稱 53
表4- 1 觸媒組成分析 59
表4- 2觸媒之氮氣吸脫附詳細結果 66
表4- 3觸媒之路易斯酸與布朗斯特酸酸量結果 72
表4- 4觸媒之路易斯酸與布朗斯特酸酸量結果(pyridine-IR) 75
表4- 5觸媒於450 oC和500 oC之MTA反應結果(轉化率100%) 83

 
圖目錄
圖1- 1 2014年至2019年世界甲醇的生產與需求變化 1
圖2- 1不同zeolites之結構示意圖 5
圖2- 2沸石觸媒在不同孔洞選擇性的反應路徑 5
圖2- 3反應物動力學直徑與觸媒孔洞比較之示意圖 6
圖2- 4沸石觸媒之Lewis acid site及Brønsted acid site示意圖 6
圖2- 5 MTA之反應途徑 8
圖2- 6 MTH之碳池機制 11
圖2- 7 HZSM-5行MTH雙循環反應機制 12
圖2- 8 HZSM-5於450 oC下的滯留時間與轉化率的關係圖 13
圖2- 9奈米尺徑和多級孔的沸石觸媒之合成方式示意圖 14
圖3- 1布拉格繞射之示意圖 20
圖3- 2 Micromeritics, ASAP2020 比表面積及孔徑分析儀 22
圖3- 3 JEM-2100F /JEOL Co.高解析穿透式電子顯微鏡 23
圖3- 4掃描式電子顯微鏡內部構造 24
圖3- 5焰炬管示意圖 26
圖3- 6在(無)磁場下原子核自旋情形 27
圖3- 7 AutoChem II 2920 自動化學吸脫附儀 28
圖3- 8自動式化學吸脫附儀結構示意圖 29
圖3- 9異丙胺於布朗斯特酸性點的分解反應 31
圖3- 10 ThermoStar GSD 320T, Pfeiffer Vacuum 四極柱質譜儀 31
圖3- 11紅外吸收光譜與其對應的分子之結構振動 40
圖3- 12 Thermo Scientific Nicolet iS50 傅立葉轉換紅外線光譜儀 41
圖3- 13原位紅外光石英池之示意圖 42
圖3- 14 X光電子能譜儀之示意圖 44
圖3- 15 TA Instruments Q600 SDT 同步熱分析儀 45
圖3- 16火焰離子偵測器示意圖 46
圖3- 17惠斯同電橋示意圖 47
圖3- 18碳氫化合物以火焰離子偵測器分析之GC圖譜 50
圖4- 1酸洗後之奈米碳管之熱重分析圖譜 57
圖4- 2 Ga/CNTs氫氣程溫還原圖譜 58
圖4- 3觸媒之XRD繞射圖譜 60
圖4- 4觸媒鍛燒後的SEM和TEM圖像 62
圖4- 5觸媒鍛燒前的SEM和TEM圖像 63
圖4- 6 (a) CNTs和(b) Ga/CNTs的TEM圖像 63
圖4- 7觸媒的氮氣等溫吸脫附曲線圖 65
圖4- 8觸媒BJH孔徑分布圖 65
圖4- 9觸媒27Al NMR 圖譜 67
圖4- 10觸媒29Si NMR 圖譜 68
圖4- 11觸媒之紅外線光譜 69
圖4- 12觸媒之氫氣程溫還原圖譜 71
圖4- 13觸媒之氨氣程溫脫附圖譜 73
圖4- 14觸媒之異丙胺程溫脫附圖譜 74
圖4- 15觸媒於350oC之Pyridine-IR圖譜 76
圖4- 16觸媒之Ga 2p軌域X射線光電子能譜 77
圖4- 17觸媒之甲醇程溫表面反應之質譜儀訊號圖譜 79
圖4- 18物理混合之觸媒(β-Ga2O3 ＆ CNT-HZ)的甲醇程溫表面 80
圖4- 19觸媒於450 oC MTA反應之GC圖譜 84
圖4- 20觸媒於500 oC下之MTA反應壽期測試 86
圖4- 21反應後各觸媒之熱重分析圖譜 87
圖4- 22反應後各觸媒熱重分析之一階微分圖譜 87

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