臺灣博碩士論文加值系統

本研究主要是配合應用於直接甲烷固態氧化物燃料電池(SOFC)的陽極催化機制和模擬導氧離子材料在積碳電池的反應機構。吾人選定Gd2O3-doped CeO2 (GDC)為擔體材料，並含浸鎳或鐵觸媒用以模擬陽極觸媒層。而實驗主要探討SOFC陽極觸媒層和甲烷催化的反應機制，並利用一系列的實驗證明導氧離子材料的傳導氧模式，最後研究探討甲烷反應後的積碳和擔體利用傳導氧的性質來產生自身去積碳的現象。
吾人用共沉澱法讓Gadolinia, Gd2O3添加入CeO2晶格中，利用電荷不平衡的結果來造成氧空洞，而此特殊的缺陷會在晶格表面以及內部都會存在。利用XRD來分析擔體發現，在120℃時即可讓Gd2O3添加入CeO2晶格中，且由BET方法知道在此溫度下具有122.9m2/g的表面積，而隨著煅燒溫度提升表面積會迅速下降。
利用氫氣或一氧化碳程溫還原，以及二氧化碳程溫氧化的手法分析鑑定此具有特殊缺陷的陶瓷材料內部和表面性質。由實驗發現在足夠的溫度內，導氧離子材料內部晶格氧會傳導到氧空位上和反應物反應，而這樣的結果將導致TPR或TPO的反應訊號線不會回虧基線，並且證明晶格氧的傳導將是反應控制的步驟。
由甲烷的程溫反應可以發現: GDC和甲烷的反應活性位發生在GDC的表面氧，而當GDC沒有表面氧存在時，甲烷反應則無法進行，直到溫度升溫至內部晶格氧可以補充至表面時，反應才得以進行。在低溫處甲烷和表面氧作用將多產生二氧化碳；當反應到高溫與內部補充到表面的晶格氧作用時，將多產生一氧化碳。
自身去積碳的實驗發現，在低溫處是多產生二氧化碳，也是因為豐富的表面氧濃度所造成；而當反應到高溫，利用晶格氧的去積碳則多產生一氧化碳，這樣的結果與甲烷的程溫反應吻合。含浸鎳的GDC觸媒具有最佳的自身去積碳效果；而含浸鐵的觸媒具有穩定的去積碳能力，這是由於含浸鐵後，會讓表面具有豐富的表面氧濃度所導致。
水氣的吸附解離實驗發現，含浸鐵的觸媒具有比鎳佳的吸附解離能力，意味了水氣的存在，將比較優先吸附在鐵觸媒

目 錄

第一章.緒論 -------------1
第二章.理論與文獻回顧 -------------4
2-1甲烷的相關反應方程式 -------------4
2-2水氣轉移反應 (WGS) -------------8
2-3導氧離子氧化物與氧空洞擔體 ------------10
2-3.1導氧離子氧化物 ------------10
2-3.2氧空洞擔體 ------------12
2-4積碳去除的方法及其相關研究 ---------------13
2-5積碳─去積碳處理的相關研究 -----------15
2-6觸媒的選擇 ------------19
第三章.實驗方法與步驟 ------------20
3-1實驗藥品 ------------20
3-2製備方法 ------------20
3-2.1擔體製備 ------------20
3-2.2. Ni-Fe/觸媒製備 ------------21
3-3實驗裝置與實驗方法 ------------21
3-3.1.活性測試儀器 ------------21
3-3.2.X-Ray測量 ------------22
3-3.3 BET表面積測試 ------------22
3-3.4程溫還原 ------------23
3-3.5甲烷程溫反應 ------------23
3-3.6自身去積碳的實驗 ------------23
3-3.7二氧化碳程溫氧化實驗 ------------24
3-3.8水氣於觸媒表面解離產生氫氣實驗 ------------25

第四章.實驗結果與討論 ------------29
4-1擔體的X光繞射分析(XRD) ------------29
4-2擔體BET表面積測試 ------------33
4-3程溫還原實驗(TPR) ------------34
4-4證明內部晶格氧往表面氧空缺補充之實驗 ------------41
4-5二氧化碳程溫氧化實驗(CO2-TPO) ------------49
4-6甲烷程溫反應 (CH4-TPRx) ------------52
4-6.1 GDC甲烷程溫反應實驗 ------------52
4-6.2不同溫度還原下的GDC－甲烷程溫反應實驗 ------------55
4-6.3 GDC的甲烷程溫反應機構推導 ------------60
4-6.4 Ni/GDC甲烷程溫反應機構 ------------63
4-6.5甲烷程溫反應的綜合討論與比較 ------------67

4-7自身去積碳(Self-Decoking)實驗 ------------70
4-7.1證明導氧離子材料具有自身去積碳能力之實驗-----------70
4-7.2減少甲烷反應時間對於自身去積碳的影響與探討---------79
4-7.3以60%鎳的觸媒含浸量對於自身去積碳的影響與探討------86
4-7.4 1Ni-0.1Fe/GDC自身去積碳實驗 ------------89
4-7.5導氧離子材料自身去積碳機構 ------------91
4-7.6不同還原溫度對自身去積碳的影響 ------------95
4-8水氣於觸媒表面吸附解離實驗 ----------103

第五章.結論 ----------105

第六章.未來研究方向 ----------107

參考文獻 ----------108

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