摘要
本專題論文是利用密度泛函理論(DFT)的計算方法來探討如何利用乙炔分子去進行鎳(Ni)電極的去硫化現象。由我們的計算結果發現，在S/C2H2/Ni(100)系統中最為穩定的吸附結構為NiS(D)和NiC2H2(D)，且其吸附能分別為-126.2 kcal/mol和-50.43 kcal/mol。於Ni(100)表面的去硫化反應將遵循著Langmiur-Hinshelwood (LH)及Eley-Rideal (ER)兩個不同的反應機制。其中，於Ni(100)表面透過LH機制所進行的第一及第二次合成過程(形成C2H2S和C4H4S吸附中間物)中所需的S原子和2C2H2分子的反應活化能為57.1 kcal/mol和77.1 kcal/mol 。透過ER機制所進行的反應亦將於論文中詳細介紹，其相對應的反應活化能為38.7 kcal/mol和40.3 kcal/mol。經由上述兩者的反應結果比較，硫原子透過乙炔分子協助在Ni(100)的去硫化反應比較喜歡透過ER機制而不是LH機制。
Abstract
The resistance to sulfur poisoning of Ni(100) surface with the assistance of acetylene moleculeswere systematically investigated using thedensity functional theory method.Based on our calculated consequences, we found that the NiS(D) and NiC2H2(D) are calculated to be the two most stable conformers, possessing adsorption energies of-126.2 kcal/moland -50.43 kcal/mol, among all calculated structures of S/C2H2/Ni(100) system. In addition, the calculated activation energies for the first and second combination processes (formations of C2H2Sand C4H4S adsorbed intermediates) of S and 2C2H2 on Ni(100) surface via Langmuir- Hinshelwood (LH) reaction pathway, are 57.1 and 77.1 kcal/mol, respectively. Reaction paths via Eley-Rideal (ER) reaction pathwaywere also explored in detail, and the corresponding activation barriers are calculated to be 38.7 and 40.3 kcal/mol, respectively. Our calculated results show that the the resistance to sulfur poisoning of Ni(100) surface by acetylene molecules will be easily followed through ER mechanism rather than LH mechanism.
