臺灣博碩士論文加值系統

本研究以活性碳(Vulcan XC-72)為支撐物，利用沉澱析出法製得一系列修飾的鉑陽極觸媒:PtCe/C、PtSn/C、PtCo/C及PtRu/C。以XRD和TEM鑑定支撐性觸媒結構及顆粒大小；以TPR了解觸媒的還原情形，及添加物與鉑觸媒之間的作用力。為進一步了解觸媒性質與催化活性的關聯，配合循環伏安法(CV)的測試，確認鉑陽極觸媒對氧化乙醇的電化學活性及CO消除能力。
XRD與TEM的鑑定顯示，所製備的陽極觸媒都具有相當高的金屬分散度，由TPR得知金屬與氧化物之間的作用力強。由CV測試氧化乙醇電化學活性得知，經添加物修飾的Pt/C觸媒均有良好的活性，
1. 在PtCo/C、PtRu/C觸媒中，係因CoO及Ru能促使CO的消除使得CO毒化的現象減低而提升活性。所以隨著CoO及Ru含量的增加，消除CO的效果就愈明顯，在此兩種觸媒中以20Pt30Co及20Pt30Ru的活性最佳。
2. 在PtSn/C觸媒中，以PtSn合金型態能有效促使C-C鍵的裂解，使得反應順利進行而提升活性。隨Sn的含量增加，Pt被包覆的情況就愈嚴重，而使Pt的活性位置減少，造成活性的下降，在此系列觸媒中以20Pt10Sn活性最佳。
3. 在PtCe/C觸媒中，CeO2確實能夠增加觸媒的分散度，使得反應活性面積增加而提升活性，在此系列觸媒中以20Pt20Ce活性最佳。

In this study, Pt-based anode catalysts have been prepared by the deposition-precipitation method (DP) and commercial carbon black (Vulcan XC-72) was used as the support. Effects of modification on activity of Pt/C catalysts by second materials were pursued and including: CeO2, CoO, Sn, and Ru. The information about particle size and catalyst structure were physically characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The technique of temperature programmed reduction (TPR) was used to explore the reductive behavior of the oxidized catalysts and also the interaction between platinum and second materials. The catalytic activity of the Pt-based anode catalysts toward electro-oxidation of ethanol was examined by cyclic voltammetry (CV).
TEM and XRD examinations indicated that metal crystallites were finely dispersed on the reduced catalyst. TPR characterization suggested that deposited metallic crystallites strongly interacted with the oxide species. The activity of Pt-based catalysts was found promoted by incorporation of second material. Based on our findings, the following conclusions can be drawn:
1. In the PtCo/C and PtRu/C catalysts, the CO-poisoning effect can be significantly released by the incorporation of CoO and Ru, respectively. The promotion effect was increased by the amount of second materials. As a result, 20Pt30Co and 20Pt30Ru showed the best electrochemical activity for ethanol oxidation.
2. For Sn modified Pt/C catalyst, the formation of PtSn alloy enhanced the probability for broke the C-C bond. However, the amount of tin used for PtSn/C promotion is limitated. A further increase in Sn content would occlude a large fraction of platinum crystallites attributed by the decreased of available Pt site for ethanol electro-oxidation. The promotion by Sn is optimized at 10% in catalyst composition (20Pt10Sn).
3. The promoting role of ceria for ethanol oxidation has been attributed to an increased dispersion of Pt crystallites. As the result, 20Pt20Ce showed the best electroactivity.

誌謝 ii
摘要 iii
ABSTRACT iv
目錄 vi
表目錄 ix
圖目錄 x
1. 緒論 1
1.1 綠色燃料 1
1.2 燃料電池的發展現況 1
1.3 直接乙醇燃料電池工作原理 3
1.4 DEFC陽極觸媒的發展 5
1.5 陽極觸媒文獻回顧 7
1.6 研究動機及目的 12
2. 實驗 13
2.1 藥品 13
2.2 觸媒的製備 13
2.2.1 Pt/C觸媒之製備 13
2.2.2 PtCe/C觸媒之製備 13
2.2.3 不同溫度下PtCe/C觸媒之製備 16
2.2.4 PtSn/C觸媒之製備 17
2.2.5 PtCo/C觸媒之製備 17
2-2.6 PtRu/C觸媒之製備 17
2.3 觸媒特性鑑定 18
2.3.1 金屬負載量量測 18
2.3.2 X光粉末繞射儀 18
2.3.3 穿透式電子顯微鏡 18
2.3.4 程溫還原 19
2.4 電化學活性測試 22
2.4.1 電極製備 22
2.4.2 循環伏安法 22
2.4.3 CO消除 22
3. 結果與討論 24
3.1 PtCe/C觸媒特性鑑定及活性測試 24
3.1.1 XRD和TEM分析 24
3.1.2 TPR分析 28
3.1.3 CV活性測試 35
3.1.4 PtCe-60觸媒分佈示意圖 42
3.2 PtCo/C觸媒特性鑑定及活性測試 42
3.2.1 XRD和TEM分析 42
3.2.2 TPR分析 46
3.2.3 CV活性測試 46
3.2.4 PtCo觸媒分佈示意圖 46
3.3 PtSn/C 50
3.3.1 XRD和TEM分析 50
3.3.2 TPR分析 50
3.3.3 CV活性測試 55
3.3.4 PtSn觸媒分佈示意圖 55
3.4 PtRu/C觸媒特性鑑定及活性測試 58
3.4.1 XRD和TEM分析 58
3.4.2 TPR分析 58
3.4.3 CV活性測試 62
3.4.4 PtRu觸媒分佈示意圖 62
3.5 CO消除 65
4. 結論 68
參考文獻 70
自 傳 74

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