本論文使用密度泛函理論的計算來探討乙醇在α-Al2O3(0001) 和3Ni/α-Al2O3(0001) 表面吸附和裂解反應，以及在3Cu/α-Al2O3(0001) 表面的水氣轉移反應，包含產物結構、吸附能以及反應位能圖等的計算。我們亦透過態密度以及電子密度差異的分析，來探討吸附物質與表面的作用力。計算結果顯示，乙醇在α-Al2O3(0001) 表面的裂解反應，主要產物為乙烯 (CH3CH2OH(a) → C2H4(g) + OH(a) + H(a))，反應能障為1.46 eV，此說明了實驗的觀察：在α-Al2O3(0001) 表面，雖然有很高的乙醇轉化率，但其產氫量低。反之，乙醇在3Ni/α-Al2O3(0001) 表面上的裂解反應，可藉由鎳吸附在α–Al2O3 (0001) 表面，增加催化表面的反應性，也降低表面積碳現象的產生。在形成CH2CHO反應中間體時，可以藉由吸附位置的轉換，來增加碳原子的配位數，同時減弱C–C鍵的鍵能，使其容易斷裂 (CH2CH2O(a) → CH2CHO (a) + H(a))，此步驟為整體反應當中的速率決定步驟，反應能障為1.20 eV。另一方面，我們同樣藉由銅吸附在α–Al2O3 (0001)表面，研究在3Cu/α-Al2O3(0001) 表面上水氣轉移反應。計算結果指出，OH扮演相當重要的催化角色，可經由water dimer的裂解取代直接單一的水裂解，不但大幅降低水氣轉移反應中，水裂解反應第一步所需克服的能障，進而提高OH的覆蓋率。OH的存在不但可增加CO的轉化率，同時可提高H2產率。其中產氫能障只需0.65 eV。

Ethanol adsorption and decomposition on the clean α-Al2O3(0001) and the 3Ni/α-Al2O3(0001) surfaces, and water gas shift reaction on 3Cu/α-Al2O3(0001) surface have been systematically investigated by the density functional theory calculations. The nature of the surface–adsorbates bonding was studied through the analyses of density of states (DOS) and the electron density difference (EDD) contour plots. Although the experimental observation showed that the α-Al2O3(0001) surface has high ethanol conversion, but the calculated results indicate that ethanol dehydration to ethylene (CH3CH2OH(a) → C2H4(g) + OH(a) + H(a)), is the main reaction pathway with the energy barrier of 1.46 eV. Whereas the ethanol decomposition over the 3Ni/α-Al2O3(0001) surface shows that the 3Ni/α-Al2O3(0001) surface possesses high activity to inhibit coke formation and the CH2CH2O(a) → CH2CHO(a) + H(a) reaction is the rate-determining step for the overall reaction [CH3CH2OH(a) → CH2(a) + CO(a) + 4H(a) ] with an energy barrier of 1.20 eV. The water gas shift reaction mechanisms (redox, carboxyl and formate) on the 3Cu/α-Al2O3(0001) surface, have been examined. The calculated results show that the redox and carboxyl mechanisms are controlled by OH diffusion and carboxyl formation, respectively. These studies suggest that the OH is a reactive intermediate and plays an autocatalytic role in the catalytic WGS reaction. Specially, the OH formation barrier can be reduced to 0.22 eV from the water dimer dissociation, and the H2 formation barrier is extremely low, 0.65 eV, on 3Cu/α-Al2O3(0001) surface.

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