Pd(111)点缺陷表面乙炔加氢生成乙烯的密度泛函理论研究

摘要

本文通过密度泛函理论(DFT)研究Pd(111)表面上点缺陷对乙炔加氢生成乙烯反应的影响。计算结果表明乙炔,乙烯基和乙烯的结合能在Pd(111)和Pd(111)点缺陷表面按照Pd(111) Pd-fd Pd-sd的顺序递减。Pd-fd表示点缺陷在第一层,Pd-sd表示点缺陷在第二层。乙炔加氢生成乙烯基的能垒在Pd(111)表面上最大,在Pd-sd表面上最小,而乙烯基加氢生成乙烯的能垒在Pd(111)表面上最大,但是在Pd-fd表面上最小。因此Pd(111)表面上点缺陷的存在提高了乙炔加氢生成乙烯反应的活性。The hydrogenation of acetylene to ethylene on the Pd(111) surface with point defect is explored by Density Functional Theory (DFT). The results show that the binding energies of acetylene, vinyl and ethylene on the Pd(111) and the Pd(111) with point defect are decreased as the trend of Pd(111) Pd-fd Pd-sd. The Pd-fd represents the point defect on the first layer, the Pd-sd represents the point defect on the second layer. The reaction barrier of acetylene hy- drogenation to vinyl is maximum on the Pd(111) surface and minimum on the Pd-sd surface, and the barrier of vinyl hydrogenation to ethylene is also maximum on the Pd(111) surface but minimum on the Pd-fd surface. The result shows that the presence of point defect in the Pd(111) surface promotes the activity of the hydrogenation of acetylene.