催化学报

催化学报 ›› 2014, Vol. 35 ›› Issue (3): 294-301.DOI: 10.1016/S1872-2067(12)60730-X

• 研究论文 • 上一篇    下一篇

原位漫反射傅里叶变换红外光谱研究锰铁基催化剂上低温选择性催化还原反应机理

陈婷, 管斌, 林赫, 朱霖   

  1. 上海交通大学动力机械及工程教育部重点实验室, 上海200240
  • 收稿日期:2013-08-21 修回日期:2013-10-15 出版日期:2014-02-26 发布日期:2014-02-26
  • 通讯作者: 林赫
  • 基金资助:

    国家自然科学基金（51176118，51306115）；中国博士后科学基金（2012M520894，2013T60445）.

In situ DRIFTS study of the mechanism of low temperature selective catalytic reduction over manganese-iron oxides

Ting Chen, Bin Guan, He Lin, Lin Zhu   

  1. Key Laboratory for Power Machinery and Engineering of Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2013-08-21 Revised:2013-10-15 Online:2014-02-26 Published:2014-02-26
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (51176118, 51306115) and the China Postdoctoral Science Foundation (2012M520894, 2013T60445).

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687

被引次数

40

摘要：

采用自蔓延燃烧法制备了Ti0.9Mn0.05Fe0.05O2-δ催化剂，运用原位漫反射傅里叶变换红外光谱对该催化剂的NO和NH3稳态吸附以及NO和NH3瞬态反应进行了详细地分析与讨论. 结果表明，相比于Lewis酸性位，150℃时Brönsted酸性位吸附的NH3更具有SCR活性；与双齿硝酸盐和桥式硝酸盐相比，NO吸附产生的单齿硝酸盐是主要的中间物种；该SCR反应遵循Eley-Rideal和Langmuir-Hinshelwood机理，但以后者为主. 另外，O2的存在有利于NO的氧化和配位态NH3的活化.

关键词: 氮氧化物, 氨, 锰铁基催化剂, 低温选择性催化还原, 原位漫反射傅里叶变换红外光谱

Abstract:

To investigate the mechanism of selective catalytic reduction (SCR) of NOx with NH3, Ti0.9Mn0.05Fe0.05O2-δ catalyst was prepared by self-propagating high-temperature synthesis (SHS) method and evaluated at 25-450℃. The catalyst was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The possible SCR mechanism over Ti0.9Mn0.05Fe0.05O2-δ was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Ti0.9Mn0.05Fe0.05O2-δ showed both high SCR activity and N2 selectivity over a broad temperature window of 100-350℃. The XRD and TEM results indicated that the active components of Mn and Fe were in a highly dispersed state and in an amorphous form on TiO2. The DRIFTS results revealed that Brönsted acid sites were the active centers for NO removal and monodentate nitrates were the key intermediate in the SCR reaction. At 150℃, both Langmuir-Hinshelwood and Eley-Rideal mechanisms are involved in the SCR reaction, while the former one mechanism dominates the catalytic activity of Ti0.9Mn0.05Fe0.05O2-δ. Additionally, the presence of O2 significantly affects NO oxidation and coordinated NH3 activation.

Key words: Nitrogen Oxide, Ammonia, Manganese-iron catalysts, Low temperature selective catalytic reduction, In situ diffuse reflectance infrared Fourier transform spectroscopy