Density functional theory study of the adsorption and reaction of C₂H₄ on Fe₃C(100)

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• 作者：Bingyin Wang ; Xiaohu Yu ; Chunfang Huo ; Jianguo Wang ; Yongwang Li
• 关键词：Ethylene ; Cementite ; Adsorption ; Dehydrogenation ; Cleavage ; Fischer-Tropsch synthesis ; Density functional theory
• 刊名：Chinese Journal of Catalysis
• 出版年：January, 2014
• 年：2014
• 卷：35
• 期：1
• 页码：28-37
• 全文大小：1312 K

文摘

Spin-polarized density functional theory (DFT) and a periodic slab model were employed to investigate the adsorption of C₂H₄ on Fe₃C(100), which is an active phase of an Fe-based catalyst for Fischer-Tropsch synthesis. The competition between dehydrogenation and cleavage of C₂H₄ was analyzed. The 渭-bridging adsorption mode is more stable than the 蟺 or di-蟽 adsorption modes. Partial rehybridization of the C atoms of C₂H₄ (sp²鈫?em>sp³) caused by the interaction of C₂H₄ with the Fe₃C(100) surface resulted in the C atoms in C₂H₄ having a quasi-tetrahedron geometry. On Fe₃C(100) dehydrogenation of C₂H₄ occurs, while C-C bond cleavage is not competitive. The calculations indicated that vinylidene (CCH₂) and vinyl (CHCH₂) species are the most abundant C₂ species, which may be the major monomeric forms of C₂H₄ in the chain growth in Fischer-Tropsch synthesis