請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/66853
標題: | 氧化銅負載層狀雙氫氧化物於一氧化碳氧化之研究 Layered double hydroxide supported CuO on carbon monoxide oxidation |
作者: | Yu-Thung Liaw 廖宇同 |
指導教授: | 劉雅瑄(Ya-Hsuan Liou) |
關鍵字: | 層狀雙氫氧化物,協同作用,一氧化碳氧化, Layered double hydroxides,synergistic effects,carbon monoxide oxidation, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 層狀雙氫氧化物(Layered double hydroxides, LDHs)一種陰離子型黏土,具有成本低廉、以及與金屬觸媒有協同作用已被視為有潛力的觸媒載體之一。本研究利用共沉澱、剝層以及含浸三種不同的製備方式合成了三種LDH觸媒系統分別以Cu-LDH、D-LDH以及Cu/LDH命名。最後以一氧化碳氧化實驗結果篩選出含浸法製備的材料為氧化表現最佳的材料。含浸法製備的材料在有氧條件下於200°C轉化了90%的一氧化碳。在X光繞射分析可以發現,含浸法製備的20 wt% Cu/LDH材料因同時具有LDH與CuO的結晶型態,在氧化效果上相比於其他兩種觸媒系統具有更好的表現。初步推測LDH與CuO的協同作用是主導氧化的主要因素。含浸法製備的20 wt% Cu/LDH材料在經過300°C和500°C的煅燒後,可以發現在有氧條件下的氧化效果上也有明顯的差異。20 wt% Cu/LDH300具有最佳的轉化效果,於80°C開始轉化一氧化碳,在150°C就達到最高90%的轉化。而20 wt% Cu/LDH500於100°C開始轉化一氧化碳,在175°C就達到最高72%的轉化。在in-situ FTIR的實驗中可以發現造成這個差異的原因是由於在經過300°C煅燒後的材料中的碳酸根與銅有著更強的鍵結(2500 cm-1處的吸收峰) 。2500cm-1處的吸收峰在無氧氣的氧化實驗條件下會隨著溫度升高逐漸減弱並消失,結合質譜儀無氧條件氧化實驗結果觀測到二氧化碳的生成推測碳酸根在一氧化碳的氧化中是一個提供氧的角色。另外,從質譜儀無氧條件氧化實驗結果、X光電子光譜以及X光繞射分析反應後的材料,可以發現在無氧條件下反應,材料中的氧化銅在150°C就完全被還原為0價的金屬銅。本研究結果發現層狀雙氫氧化物會參與一氧化碳氧化的反應中,並扮演著提供氧的角色,降低反應啟動溫度提升氧化效率。 Layered double hydroxides(LDHs) is an anionic clay, one of the catalyst supporter that has been considered to have potential because of its low cost and synergistic effect with metal catalyst. In this research, 3 LDH catalyst were synthesized by co-precipitation, exfoliation and impregnation methods. The catalyst prepared by impregnation method has the best performance in oxidation of carbon monoxide. It converts 90% of carbon monoxide under O2 condition at 200°C. The synergistic effect between CuO and LDH was believed to be the main reason of better performance in oxidation of carbon monoxide.After calcination at 300°C and 500°C, it can be found that there is a significant difference in the carbon monoxide conversion performance under O2 condition. The catalyst calcined at 300°C has the best activity, CO started convert at 80°C and reach its maximum conversion of 90% at 150°C. However, the catalyst calcined at 500°C started convert CO at 100°C and reach its maximum conversion of 72% at 175°C. The in-situ FTIR experiment show that, reason for this difference is that the carbonate in the material after calcination at 300°C has stronger bonding with copper (absorption peak at 2500 cm-1). In the oxygen free experimental condition, the absorption peak at 2500 cm-1 decreased and disappeared as the temperature increased, combine the results of CO2 generation show by mass spectrometer, it shows that carbonate is a O supplier in this reaction. Copper oxide in catalyst is completely reduce to copper at 150°C proven by the results of XPS and XRD analysis of the catalyst after reaction. The result of this study found that LDH will participate in the oxidation of CO and play the role of providing oxygen, reducing the reaction starting temperature and increasing the oxidation efficiency. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/66853 |
DOI: | 10.6342/NTU202000174 |
全文授權: | 有償授權 |
顯示於系所單位: | 地質科學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-109-1.pdf 目前未授權公開取用 | 3.74 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。