Arevalo Ryan Lacdao, Aspera Susan Meñez, Sison Escaño Mary Clare, Nakanishi Hiroshi, Kasai Hideaki
National Institute of Technology, Akashi College, 679-3 Nishioka, Uozumi, Akashi, Hyogo 674-8501, Japan.
J Phys Condens Matter. 2017 May 10;29(18):184001. doi: 10.1088/1361-648X/aa66c7. Epub 2017 Mar 14.
Many chemical reactions that produce a wide range of hydrocarbons and alcohols involve the breaking of C-H bonds in methane. In this paper, we analyzed the decomposition of this molecule on the B5 step-edge type site of Ru surface using first principles calculations based on dispersion-corrected density functional theory. Methane was found to be weakly adsorbed on the surface, characterized by the hybridization of its sp states with Ru-d states. Dissociative adsorption is energetically preferred over molecular methane adsorption, resulting in CH fragment. CH is strongly adsorbed on the surface due to the prevalence of low-energy sp-d bonding interaction over the electron-unoccupied anti-bonding states. This highly stable CH requires higher activation barrier for C-H bond cleavage than CH.
许多生成多种碳氢化合物和醇类的化学反应都涉及甲烷中C-H键的断裂。在本文中，我们基于色散校正密度泛函理论，利用第一性原理计算分析了该分子在Ru表面的B5台阶边缘型位点上的分解情况。发现甲烷在表面上的吸附较弱，其特征是sp态与Ru-d态发生杂化。解离吸附在能量上比分子态甲烷吸附更有利，会产生CH片段。由于低能sp-d键相互作用比电子未占据的反键态更普遍，CH在表面上被强烈吸附。这种高度稳定的CH比CH需要更高的活化能垒来进行C-H键的裂解。
