Theoretical study of oxidation–reduction reaction of Fe2O3 supported on MgO during chemical looping combustion
► Properties of Fe2O3/MgO composite. ► CO/O2 adsorption on Fe2O3/MgO composite. ► Mechanism of CO oxidation by Fe2O3 related to the fuel reactor of the CLC system. ► Mechanism of Fe2O2 oxidation by O2 related to the air reactor of the CLC system. We applied density-functional theory (DFT) in periodi...
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Published in | Applied surface science Vol. 266; pp. 350 - 354 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Amsterdam
Elsevier B.V
01.02.2013
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | ► Properties of Fe2O3/MgO composite. ► CO/O2 adsorption on Fe2O3/MgO composite. ► Mechanism of CO oxidation by Fe2O3 related to the fuel reactor of the CLC system. ► Mechanism of Fe2O2 oxidation by O2 related to the air reactor of the CLC system.
We applied density-functional theory (DFT) in periodic system to investigate the two reactions (CO+Fe2O3/MgO→CO2+Fe2O2/MgO, O2+Fe2O2/MgO→O+Fe2O3/MgO) in chemical looping combustion system. While Fe2O3 was supported on MgO(100) surface Fe2O3 gathered together to form a cluster shape on MgO(100), denoted as Fe2O3/MgO, where the Fe2O3 was activated by MgO(100). Then CO interacted with Fe2O3/MgO and carbonate generated during a stepwise reaction with the calculated maximum barrier energy of 0.95eV, far less than that of the reaction between CO and the pure Fe2O3 cluster (2.59eV). CO was oxidized by Fe2O3/MgO and then Fe2O3/MgO transformed into the reduced state Fe2O2/MgO, corresponding to the reaction in the fuel reactor in the CLC system. Then the breaking of the adsorbed O2 molecule on Fe2O2/MgO made an O atom bind to a Fe site with the barrier energy of 0. 20eV, which played as the key step for the oxidizing of Fe2O2/MgO by O2 into Fe2O3/MgO, corresponding to the reaction in the air reactor in the CLC system. |
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ISSN: | 0169-4332 1873-5584 |
DOI: | 10.1016/j.apsusc.2012.12.023 |