高指数晶面结构氧化铁化学链燃烧反应活性及深层还原反应机理(英文)  

Reaction Activity and Deep Reduction Reaction Mechanism of a High Index Iron Oxide Surface in Chemical Looping Combustion

作　　者：覃吴[1] 林常枫 龙东腾 肖显斌[1] 董长青[1] 

机构地区：[1]华北电力大学可再生能源学院,生物质发电成套设备国家工程实验室,北京102206

出　　处：《物理化学学报》2015年第4期667-675,共9页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(51106051);111 Project,China(B12034);Fundamental Research Funds for the Central Universities,China(2014MS36,2014ZD14)~~

摘　　要：采用密度泛函理论计算和实验研究形貌可控制备氧化铁作为高效载氧体用于化学链燃烧的可行性.首先从理论上对比分析Fe2O3高指数晶面[104]和低指数晶面[001]的反应活性及深层还原反应机理.表面反应结果显示,Fe2O3[104]氧化CO的反应活性远高于Fe2O3[001],Fe2O3[104]被还原成为低价的铁氧化物或单质,这些低价的铁氧化物或单质可被O2氧化再生.载氧体和CO深层反应结果显示Fe2O3[104]可被CO彻底还原成Fe单质,Fe2O3[104]释放氧能力强,反应活性高;而Fe2O3[001]还原到一定程度后反应能垒高,抑制表面进一步还原,释放氧能力有限.最后,实验结果进一步证明了Fe2O3[104]作为载氧体用于化学链燃烧的高反应活性及稳定性.The possibility of morphological control of iron oxide as an oxygen carrier for chemical looping combustion was investigated using density functional theory and experiment. First, we calculated the reactivity of Fe2O3 with high-index facets [104] and low-index facets [001], as well as the deep reduction reaction mechanism of these two facets. Surface reaction results show that the activity of Fe203[104] for oxidizing CO is greater than that of Fe203[001]. Fe2O3[104] was reduced into iron oxide at lower oxidation state or into iron, which could then be regenerated after being oxidized by O2. The deep reduction reaction mechanism between oxygen carrier and CO shows that Fe203O104] can be completely reduced into Fe, and Fe203[104] exhibits high oxygen transfer ability. However, Fe203[001] can only be reduced to a limited extent, with a high energy barrier preventing further reduction, while it also exhibits limited oxygen transfer capacity. Results of experiments further verify the high reactivity and stability of Fe203[104].

关 键 词：燃烧 表面 吸附 FE2O3 密度泛函理论 

分 类 号：O643.21[理学—物理化学]