水蒸气对新鲜和老化的MnOx-NbOx-CeO2催化剂的NH3-NO/NO2选择性催化还原性能的影响
Effect of water vapor on NH3-NO/NO2 SCR performance of fresh and aged MnOx-NbOx-CeO2 catalysts.
作者信息
Chen Lei, Si Zhichun, Wu Xiaodong, Weng Duan, Wu Zhenwei
机构信息
State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
出版信息
J Environ Sci (China). 2015 May 1;31:240-7. doi: 10.1016/j.jes.2014.07.037. Epub 2015 Feb 20.
A MnOx-NbOx-CeO2 catalyst for low temperature selective catalytic reduction (SCR) of NOx with NH3 was prepared by a sol-gel method, and characterized by NH3-NO/NO2 SCR catalytic activity, NO/NH3 oxidation activity, NOx/NH3 TPD, XRD, BET, H2-TPR and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that the MnOx-NbOx-CeO2 catalyst shows excellent low temperature NH3-SCR activity in the temperature range of 150-300°C. Water vapor inhibits the low temperature activity of the catalyst in standard SCR due to the inhibition of NOx adsorption. As the NO2 content increases in the feed, water vapor does not affect the activity in NO2 SCR. Meanwhile, water vapor significantly enhances the N2 selectivity of the fresh and the aged catalysts due to its inhibition of the decomposition of NH4NO3 into N2O.
采用溶胶-凝胶法制备了用于NH₃低温选择性催化还原（SCR）NOₓ的MnOx-NbOx-CeO₂催化剂，并通过NH₃-NO/NO₂ SCR催化活性、NO/NH₃氧化活性、NOₓ/NH₃ TPD、XRD、BET、H₂-TPR和原位漫反射红外傅里叶变换光谱（DRIFTS）对其进行了表征。结果表明，MnOx-NbOx-CeO₂催化剂在150-300°C温度范围内表现出优异的低温NH₃-SCR活性。在标准SCR中，由于水蒸气对NOₓ吸附的抑制作用，其会抑制催化剂的低温活性。随着进料中NO₂含量的增加，水蒸气在NO₂ SCR中不影响活性。同时，由于水蒸气抑制了NH₄NO₃分解为N₂O，其显著提高了新鲜催化剂和老化催化剂的N₂选择性。
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