乙醇在二氧化鈰金屬催化系統上之吸附及轉化

Ethanol Adsorption and Conversion over Ceria Catalyst System

廖恆毅

指導教授 ： 張一知 ； 徐新光

國立臺灣師範大學/理學院/化學系/碩士(2009年)

摘要

針對乙醇在一系列以CeO2 及 SiO2 為載體的觸媒上之吸附和轉化現象進行研究以進一步了解乙醇的重組反應。首先製備出這一系列的觸媒，並對其進行氮氣表面吸脫附、Ｘ光粉末繞射、 溫度程序控制還原、乙醇脈衝吸附、溫度程序控制脫附、乙醇脈衝反應等鑑定及測試。實驗結果顯示，經氧化處理的觸媒表面表現出較還原處理的觸媒更高的乙醇吸附量，且其吸附機制似乎亦有所不同。乙醇重組反應在單純的CeO2表面上即可能完成。在Pt/SiO2中Pt的參與作用僅在於促進表面吸附物種的分解，藉此加速反應進行的流程。但就長時間作用而言，Pt的存在會造成觸媒反應性衰減。Pt/SiO2和Pt/Ce/SiO2均表現出較預期良好的乙醇轉化能力，且沒有出現觸媒反應性衰減的情形。在Pt/SiO2表現出可觀乙醇吸附及轉化能力的同時，單純SiO2和diluted Pt (混合PtO2和SiO2)的表面上似乎完全沒有乙醇吸附。因此在Pt/SiO2上觀察到的吸附及轉化能力可能與Pt及SiO2之間的連結作用有關。

關鍵字

乙醇 ； 二氧化鈰 ； 重組反應

並列摘要

Ethanol adsorption and conversion on a series of CeO2- and SiO2- supported catalysts was investigated in order to further understand about ethanol reforming process. These CeO2- and SiO2- supported catalysts were prepared and characterized through N2 physisorption, X-ray diffraction (XRD), temperature programmed reduction (TPR), ethanol pulse chemisorption, temperature programmed desorption (TPD), and ethanol pulse reaction. The result indicated that oxidation pretreatment sample can not only adsorb ethanol, but also shows greater ethanol adsorption than that of reduction pretreatment sample. And the mechanisms of ethanol adsorption for reduced and oxidized surface seems to be different. The ethanol reforming process can be accomplished by bare CeO2. For Pt/CeO2 catalyst, participation of Pt merely accelerates some steps in the process by promoting the decomposition of adsorbed ethanol and making it feasible at lower temperature. For the long time, Pt causes deactivation of catalyst. Both of Pt/SiO2 and Pt/Ce/SiO2 shows unexpected good ethanol conversion capability and deactivation of these catalysts were not observed. Pt/SiO2 reveals considerable ethanol adsorption and conversion capability while both of bare SiO2 and diluted Pt (PtO2 and SiO2 mixed) showed no sign of ethanol adsorption and conversion. That may imply that ethanol adsorption on Pt/SiO2 associates with the interaction between Pt and SiO2.

並列關鍵字

ethanol ； ceria ； reforming

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