Role of CO2 in ethylbenzene dehydrogenation over Fe2O3(0001) from first principles

被引:14
作者
He, Xiao-Xiang [1 ]
Fan, Chen [1 ]
Gu, Xiong-Yi [1 ]
Zhou, Xing-Gui [1 ]
Chen, De [2 ]
Zhu, Yi-An [1 ]
机构
[1] E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China
[2] Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, N-7491 Trondheim, Norway
关键词
DFT; Ethylbenzene dehydrogenation; CO2; Fe2O3(0001); TOTAL-ENERGY CALCULATIONS; OXIDE-BASED CATALYST; OXIDATIVE DEHYDROGENATION; CARBON-DIOXIDE; FE2O3/AL2O3; CATALYSTS; SURFACE SCIENCE; STYRENE; ALPHA-FE2O3(0001); ADSORPTION; REACTIVITY;
D O I
10.1016/j.molcata.2011.05.002
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
First-principles calculations based on density functional theory have been performed to elucidate the reaction mechanism for ethylbenzene dehydrogenation and the role of CO2 in H removal. On the basis of the experimental information and theoretical prediction, three model surfaces with Fe-, ferryl- and O-termination are constructed to represent the active Fe2O3(0 0 0 1) surface. The calculated results indicate that on all of the three surfaces the C-H activation in the methylene group followed by the dehydrogenation of the methyl group is kinetically more favorable. The energy barriers for ethylbenzene dehydrogenation are lowest on the O-terminated surface, but the generated styrene is adsorbed too strongly to be released. As CO2 decomposition and the formation of HCOO are hindered by the relatively high activation energies, CO2 cannot serve as the oxidant to recover the O- and ferryl-terminated surfaces to keep the redox cycle. At the steady state of the reaction the coupling mechanism dominates on the Fe-terminated surface, with the synergistic effect between ethylbenzene dehydrogenation and the reverse water-gas shift reaction. Since the energy barrier for the formation of COOH is comparable to that for H-2 formation, both the one-step and two-step pathways are predicted to contribute to the coupling mechanism, although the former is more probable. (C) 2011 Elsevier B.V. All rights reserved.
引用
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页码:53 / 61
页数:9
相关论文
共 48 条
  • [1] AN INFRARED STUDY OF THE DEHYDROGENATION OF ETHYLBENZENE TO STYRENE OVER IRON-BASED CATALYSTS
    ADDIEGO, WP
    ESTRADA, CA
    GOODMAN, DW
    ROSYNEK, MP
    [J]. JOURNAL OF CATALYSIS, 1994, 146 (02) : 407 - 414
  • [2] Iron oxide-based honeycomb catalysts for the dehydrogenation of ethylbenzene to styrene
    Addiego, WP
    Liu, W
    Boger, T
    [J]. CATALYSIS TODAY, 2001, 69 (1-4) : 25 - 31
  • [3] On the geometric structure of the (0001)hematite surface
    Alvarez-Ramírez, F
    Martínez-Magadán, JM
    Gomes, JRB
    Illas, F
    [J]. SURFACE SCIENCE, 2004, 558 (1-3) : 4 - 14
  • [4] Screening of catalysts in the oxidative dehydrogenation of ethylbenzene with carbon dioxide
    Badstube, T
    Papp, H
    Dziembaj, R
    Kustrowski, P
    [J]. APPLIED CATALYSIS A-GENERAL, 2000, 204 (01) : 153 - 165
  • [5] Oxidative dehydrogenation of ethylbenzene with carbon dioxide on alkali-promoted Fe active carbon catalysts
    Badstube, T
    Papp, H
    Kustrowski, P
    Dziembaj, R
    [J]. CATALYSIS LETTERS, 1998, 55 (3-4) : 169 - 172
  • [6] Ab initio thermodynamics of oxide surfaces:: O2 on Fe2O3(0001) -: art. no. 195409
    Bergermayer, W
    Schweiger, H
    Wimmer, E
    [J]. PHYSICAL REVIEW B, 2004, 69 (19): : 195409 - 1
  • [7] PROJECTOR AUGMENTED-WAVE METHOD
    BLOCHL, PE
    [J]. PHYSICAL REVIEW B, 1994, 50 (24): : 17953 - 17979
  • [8] Boudart M., 1997, Handbook of heterogeneous Catalysis, P1
  • [9] Fe termination for α-Fe2O3(0001) as grown by oxygen-plasma-assisted molecular beam epitaxy
    Chambers, SA
    Yi, SI
    [J]. SURFACE SCIENCE, 1999, 439 (1-3) : L785 - L791
  • [10] Beneficial effect of carbon dioxide in dehydrogenation of ethylbenzene to styrene over zeolite-supported iron oxide catalyst
    Chang, JS
    Park, SE
    Park, MS
    [J]. CHEMISTRY LETTERS, 1997, (11) : 1123 - 1124