Theoretical study of oxidation-reduction reaction of Fe₂O₃ supported on MgO during chemical looping combustion

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• 作者：Wu Qin ; ^{qinwugx@yahoo.com.cn} ; Qiuluan Chen ; Yang Wang ; Changqing Dong ; ^{cqdong1@163.com} ; Junjiao Zhang ; Wenyan Li ; Yongping Yang
• 关键词：Chemical-looping combustion ; Fe2O3 ; MgO ; CO ; DFT
• 刊名：Applied Surface Science
• 出版年：2013
• 出版时间：1 February, 2013
• 年：2013
• 卷：266
• 期：Complete
• 页码：350-354
• 全文大小：718 K

文摘

We applied density-functional theory (DFT) in periodic system to investigate the two reactions (CO + Fe₂O₃/MgO ¡ú CO₂ + Fe₂O₂/MgO, O₂ + Fe₂O₂/MgO ¡ú O + Fe₂O₃/MgO) in chemical looping combustion system. While Fe₂O₃ was supported on MgO(1 0 0) surface Fe₂O₃ gathered together to form a cluster shape on MgO(1 0 0), denoted as Fe₂O₃/MgO, where the Fe₂O₃ was activated by MgO(1 0 0). Then CO interacted with Fe₂O₃/MgO and carbonate generated during a stepwise reaction with the calculated maximum barrier energy of 0.95 eV, far less than that of the reaction between CO and the pure Fe₂O₃ cluster (2.59 eV). 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. 20 eV, 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.