- 學位論文
以理論計算方法探討乙醇和甲醇在nNi/gamma-Al2O3(110)(n=1,2)表面的脫氫反應
Computational Studies of the Ethanol and Methanol Dehydrogenation Mechanisms on a nNi/gamma-Al2O3(110)(n=1,2) Surface
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摘要
我們利用periodic DFT的方法，計算乙醇和甲醇在1-2Ni/gamma-Al2O3(110)表面的吸附結構和分解路徑。在我們的研究當中，乙醇和甲醇利用OH基吸附在表面的鋁原子上有較好的吸附能，計算的結果分別為-1.61eV和-1.41eV。 在乙醇反應的探討當中，乙醇會在表面上形成四圓環或五圓環的結構，其中，四圓環的中間產物最後經過1.60 eV的能障後會斷C-C鍵形成CH3 + CO，而五圓環的中間產物會斷C-O鍵形成乙烯，所需要克服的能障為1.27 eV。甲醇可能經過脫氫反應形成一氧化碳，所需要克服的最大能障為1.27eV，而甲醇斷C-O鍵形成CH3 + OH所需要克服的能障為1.51eV。乙醇在我們模擬的情況當中有較佳的吸附能，且甲醇在整個反應當中所需要克服的能障在比較上相對比乙醇大。
並列摘要
We applied periodic density-functional theory (DFT) to investigate the dehydrogenation reactions of ethanol and methanol on 1-2Ni/gamma-Al2O3 (110) surfaces. In our studies, ethanol and methanol favor the adsorption orientation by using the OH group bonding to the Al atom on the surface; the adsorption energies were calculated to be -1.61 eV and -1.41 eV respectively. In our calculation, ethanol may form a four or five-membered ring structure on the surface. The four-membered ring intermediate could break the C-C bond to form CH3(a) + CO(a) with a dissociation barrier of 1.60 eV. And that of the five-membered ring would break the C-O bond to form ethylene with the barrier of 1.27 eV. Methanol may proceed dehydrogenation to produce carbon monoxide with a barrier of 1.27 eV, or to break the C-O bond to form CH3(a) + CO(a) with a barrier of 1.51 eV. In our calculation, we found out that ethanol had a larger adsorption energy, but methanol had higher barriers as compare to ethanol in the processes of dehydrogenation mechanisms.
參考文獻
(62)林志興，顏正濱”乙醇在Pt(111)表面上的解離反應與推拉電子基分子系統的分子動態模擬之電子轉移理論研究”淡江大學化學學系碩士班碩士論文,2009
(4)Ammendola, P.; Chirone,R.; Ruoppolo, G.; Russo, G.J. Mol. Catal. A 2007, 266, 31.
Catal., A 2003, 249, 119.
(9)Cavallaro, S. Energy Fuels 2000, 14, 1195.
(12)Vaidya, P. D.; Rodrigues, A. E. Chem. Eng. J. 2006, 117, 39.