物理化学学报 >> 2015, Vol. 31 >> Issue (4): 667-675.doi: 10.3866/PKU.WHXB201502061

理论与计算化学 上一篇    下一篇

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

覃吴, 林常枫, 龙东腾, 肖显斌, 董长青   

  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
  • 收稿日期:2014-10-13 修回日期:2015-02-06 发布日期:2015-04-03
  • 通讯作者: 覃吴 E-mail:qinwugx@126.com
  • 基金资助:

    国家自然科学基金(51106051), 111计划(B12034)和中央高校基金(2014MS36, 2014ZD14)资助项目

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

QIN Wu, LIN Chang-Feng, LONG Dong-Teng, XIAO Xian-Bin, DONG Chang-Qing   

  1. National Engineering Laboratory for Biomass Power Generation Equipment, School of Renewable Energy Engineering, North China Electric Power University, Beijing 102206, P. R. China
  • Received:2014-10-13 Revised:2015-02-06 Published:2015-04-03
  • Contact: QIN Wu E-mail:qinwugx@126.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51106051), 111 Project, China (B12034), and 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.

关键词: 燃烧, 表面, 吸附, Fe2O3, 密度泛函理论

Abstract:

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 Fe2O3[104] for oxidizing CO is greater than that of Fe2O3[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 Fe2O3[104] can be completely reduced into Fe, and Fe2O3[104] exhibits high oxygen transfer ability. However, Fe2O3[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 Fe2O3[104].

Key words: Combustion, Surface, Adsorption, Fe2O3, Density functional theory

MSC2000: 

  • O641