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Insight into CH4 Formation in Iron-Catalyzed Fischer−Tropsch Synthesis
- Source :
- Journal of the American Chemical Society. 131:14713-14721
- Publication Year :
- 2009
- Publisher :
- American Chemical Society (ACS), 2009.
-
Abstract
- Spin-polarized density functional theory calculations have been performed to investigate the carbon pathways and hydrogenation mechanism for CH(4) formation on Fe(2)C(011), Fe(5)C(2)(010), Fe(3)C(001), and Fe(4)C(100). We find that the surface C atom occupied sites are more active toward CH(4) formation. In Fischer-Tropsch synthesis (FTS), CO direct dissociation is very difficult on perfect Fe(x)C(y) surfaces, while surface C atom hydrogenation could occur easily. With the formation of vacancy sites by C atoms escaping from the Fe(x)C(y) 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, CH(4) formation is more favorable on Fe(5)C(2)(010) and Fe(2)C(011), while Fe(4)C(100) and Fe(3)C(001) are inactive toward CH(4) formation. More importantly, it is revealed that the reaction energy and effective barrier of CH(4) formation have a linear relationship with the charge of the surface C atom and the d-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.
- Subjects :
- Models, Molecular
Surface Properties
Chemistry
Carbon Compounds, Inorganic
Iron
Iron catalyzed
Molecular Conformation
Reaction energy
Fischer–Tropsch process
General Chemistry
Photochemistry
Biochemistry
Carbon
Catalysis
Dissociation (chemistry)
Colloid and Surface Chemistry
Linear relationship
Computational chemistry
Vacancy defect
Atom
Quantum Theory
Density functional theory
Hydrogenation
Methane
Iron Compounds
Subjects
Details
- ISSN :
- 15205126 and 00027863
- Volume :
- 131
- Database :
- OpenAIRE
- Journal :
- Journal of the American Chemical Society
- Accession number :
- edsair.doi.dedup.....5bcf9e6fbb06657c4c0e40b1fe321e28