催化学报 ›› 2014, Vol. 35 ›› Issue (1): 28-37.DOI: 10.1016/S1872-2067(12)60703-7

• 研究论文 • 上一篇    下一篇

C2H4在Fe3C(100)表面吸附及脱氢裂解的密度泛函理论研究

王丙寅a,b, 于小虎a, 霍春芳a,c, 王建国a, 李永旺a,c   

  1. a 中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原 030001 ;
    b 中国科学院大学, 北京 100049;
    c 中科合成油技术有限公司国家能源煤制液体燃料研发中心, 北京 101407
  • 收稿日期:2013-07-29 修回日期:2013-09-02 出版日期:2013-12-23 发布日期:2014-01-17
  • 通讯作者: 霍春芳
  • 基金资助:

    国家重点基础研究发展计划(973计划,2011CB201401);国家自然科学基金(21273261)

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).

摘要:

采用自旋极化密度泛函理论和周期平板模型,对C2H4在铁基费托合成催化剂活性相之一Fe3C(100)表面从热力学和动力学两个方面分析了C2H4在Fe3C(100)表面进行脱氢和裂解反应的竞争性。结果表明,C2H4在Fe3C(100)表面的μ-bridging吸附比π、di-σ吸附更加稳定;C2H4与Fe3C(100)面的相互作用导致C2H4的C原子部分发生重新杂化(sp2sp3),使C原子呈近四面体结构。在Fe3C(100)表面C2H4易于发生脱氢反应,C-C键裂解反应不具有竞争性。亚乙烯基CCH2和乙烯基CHCH2是Fe3C(100)表面最丰的C2物种,或是C2H4参与链增长的主要单体形式。

关键词: 乙烯, 碳化铁, 吸附, 脱氢, 裂解, 费托合成, 密度泛函理论

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