Insight into CH4 Formation in Iron-Catalyzed Fischer-Tropsch Synthesis

被引:233
作者
Huo, Chun-Fang [1 ]
Li, Yong-Wang [1 ]
Wang, Jianguo [1 ]
Jiao, Haijun [1 ,2 ]
机构
[1] Chinese Acad Sci, Inst Coal Chem, State Key Lab Coal Convers, Taiyuan 030001, Peoples R China
[2] Univ Rostock, Leibniz Inst Katalyse eV, D-18059 Rostock, Germany
基金
中国国家自然科学基金;
关键词
DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; CO ADSORPTION; SURFACES; HYDROGENATION; METHANATION; COMBUSTION; STABILITY; CARBON;
D O I
10.1021/ja9021864
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Spin-polarized density functional theory calculations have been performed to investigate the carbon pathways and hydrogenation mechanism for CH4 formation on Fe2C(011), Fe5C2(010), Fe3C(011), and Fe4C(100) We find that the surface C atom occupied sites are more active toward CH4 formation In Fischer-Tropsch synthesis (FTS), CO direct dissociation is very difficult on perfect FexCy surfaces, while surface C atom hydrogenation could occur easily. With the formation of vacancy sites by C atoms escaping from the FexCy surface, the CO dissociation barrier decreases largely As a consequence, the active carburized surface is maintained Based on the calculated reaction energies and effective barriers, CH4 formation is more favorable on Fe5C2(010) and Fe2C(011), while Fe4C(100) and Fe3C(001) are inactive toward CH4 formation. More importantly, it is revealed that the reaction energy and effective barrier of CH4 formation have a linear relationship with the charge of the surface C atom and the cl-band center of the surface, respectively On the basis of these correlations, one can predict the reactivity of all active surfaces by analyzing their surface properties and further give guides for catalyst design in FTS
引用
收藏
页码:14713 / 14721
页数:9
相关论文
共 42 条
[1]   Hydrogen adsorption on transition-metal carbide (111) surfaces [J].
Aizawa, T ;
Hayami, W ;
Souda, R ;
Otani, S ;
Ishizawa, Y .
SURFACE SCIENCE, 1997, 381 (2-3) :157-164
[2]  
Anderson RB., 1984, FISCHER TROPSCH SYNT
[3]  
[包丽丽 BAO Li-li], 2009, [燃料化学学报, Journal of Fuel Chemistry and Technology], V37, P104
[4]   Influence of intermediate iron reduced species in Fischer-Tropsch synthesis using Fe/C catalysts [J].
Bengoa, J. F. ;
Alvarez, A. M. ;
Cagnoli, M. V. ;
Gallegos, N. G. ;
Marchetti, S. G. .
APPLIED CATALYSIS A-GENERAL, 2007, 325 (01) :68-75
[5]   PROJECTOR AUGMENTED-WAVE METHOD [J].
BLOCHL, PE .
PHYSICAL REVIEW B, 1994, 50 (24) :17953-17979
[6]   Structure and energetics of iron pentacarbonyl formation at an Fe(100) surface [J].
Cheng, HS ;
Reiser, DB ;
Dean, SW ;
Baumert, K .
JOURNAL OF PHYSICAL CHEMISTRY B, 2001, 105 (50) :12547-12552
[7]   An Energy Descriptor To Quantify Methane Selectivity in Fischer-Tropsch Synthesis: A Density Functional Theory Study [J].
Cheng, Jun ;
Hu, P. ;
Ellis, Peter ;
French, Sam ;
Kelly, Gordon ;
Lok, C. Martin .
JOURNAL OF PHYSICAL CHEMISTRY C, 2009, 113 (20) :8858-8863
[8]   Structure and stability of Fe3C-cementite surfaces from first principles [J].
Chiou, WC ;
Carter, EA .
SURFACE SCIENCE, 2003, 530 (1-2) :87-100
[9]   A DFT study of CHx chemisorption and transition states for C-H activation on the Ru(1120) surface [J].
Ciobica, IM ;
van Santen, RA .
JOURNAL OF PHYSICAL CHEMISTRY B, 2002, 106 (24) :6200-6205
[10]   Fischer-Tropsch Synthesis: Reaction mechanisms for iron catalysts [J].
Davis, Burtron H. .
CATALYSIS TODAY, 2009, 141 (1-2) :25-33