催化学报 ›› 2014, Vol. 35 ›› Issue (12): 1972-1981.DOI: 10.1016/S1872-2067(14)60184-4

• 论文 • 上一篇    下一篇

聚集态的Fe氧化物在Fe/ZSM-5催化N2O直接分解中的作用

张博, 刘福东, 贺泓, 薛丽   

  1. 中国科学院生态环境研究中心, 北京100085
  • 收稿日期:2014-05-14 修回日期:2014-06-27 出版日期:2014-11-29 发布日期:2014-11-29
  • 通讯作者: 贺泓
  • 基金资助:

    国家高技术研究发展计划(863计划, 2013AA065301); 国家重点基础研究发展计划(973计划, 2010CB732304); 国家自然科学基金创新研究群体项目(51221892).

Role of aggregated Fe oxo species in N2O decomposition over Fe/ZSM-5

Bo Zhang, Fudong Liu, Hong He, Li Xue   

  1. Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
  • Received:2014-05-14 Revised:2014-06-27 Online:2014-11-29 Published:2014-11-29
  • Supported by:

    This work was supported by the National High Technology Research and Development Program of China (863 Program, 2013AA065301), the National Basic Research Program of China (973 Program, 2010CB732304), and the National Natural Science Found for Creative Research Groups of China (51221892).

摘要:

研究了以离子交换法制备的Fe/ZSM-5上聚合态的Fe氧化物(FeOx)在催化N2O直接分解中的作用.Fe/ZSM-5催化剂利用600-900 ℃的高纯Ar处理, 使催化剂中的FeOx发生聚合.利用一系列的表征手段(XRD, BET, DRIFTS, UV/vis-DRS, XAFS, N2O脉冲和O2-TPD)对催化剂进行了表征.结果发现, 分子筛骨架外的FeOx在Fe/ZSM-5催化N2O分解中起重要作用;通过研究高温处理的Fe/ZSM-5催化剂中不同FeOx的比例与催化剂活性的关系, 得到多核的FeOx是催化N2O分解的主要活性物种;并且, 无定形态的FeOx中键长较长的Fe-O键((Fe-O)2)是参与反应的重要物种.

关键词: N2O分解, Fe/ZSM-5, 铁物种, 热处理

Abstract:

The effects of aggregated Fe oxo (FeOx) species on N2O decomposition activity of aqueous ion-exchanged Fe/ZSM-5 were investigated. Aggregation of FeOx species was achieved by thermal treatment of the Fe/ZSM-5 catalysts at different temperatures (600-900 ℃) in pure Ar. The characterizations were carried out using X-ray diffraction, N2 physisorption, UV-Vis diffuse reflectance spectroscopy, X-ray absorption fine structure spectroscopy, pulse-response analysis, and O2-temperature-programmed desorption. The FeOx species on the external framework of the ZMS-5 zeolite played a dominant role in N2O decomposition over Fe/ZSM-5. By studying the relationship between the contents of the various existing iron species and activity of the different catalysts, polynuclear FeOx appeared to be the main active phase for N2O decomposition. Additionally, Fe-O with a long bond length ((Fe-O)2) in amorphous polynuclear FeOx was positively correlated to the activity of the catalysts, indicating that (Fe-O)2 was the active species for N2O decomposition.

Key words: N2O decomposition, Fe/ZSM-5, Iron species, Thermal treatment