Chinese Journal of Catalysis ›› 2014, Vol. 35 ›› Issue (1): 28-37.DOI: 10.1016/S1872-2067(12)60703-7

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

Bingyin Wanga,b, Xiaohu Yua, Chunfang Huoa,c, Jianguo Wanga, Yongwang Lia,c   

  1. a State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China;
    c National Energy R&D Center for Coal to Liquid Fuels, Synfuels China Co. Ltd, Beijing 101407, China
  • Received:2013-07-29 Revised:2013-09-02 Online:2013-12-23 Published:2014-01-17
  • Contact: Chunfang Huo
  • Supported by:

    This work was supported by the National Basic Research Program of China (973 Program, 2011CB201401) and the National Natural Science Foundation of China (21273261).

Abstract:

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 μ-bridging adsorption mode is more stable than the π or di-σ adsorption modes. Partial rehybridization of the C atoms of C2H4 (sp2sp3) 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.

Key words: Ethylene, Cementite, Adsorption, Dehydrogenation, Cleavage, Fischer-Tropsch synthesis, Density functional theory