Effect of water vapor on NH_3–NO/NO_2 SCR performance of fresh and aged MnO_x–NbO_x–CeO_2 catalysts  

作　　者：Lei Chen Zhichun Si Xiaodong Wu Duan Weng Zhenwei Wu 

机构地区：[1]State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University [2]Graduate School at Shenzhen, Tsinghua University

出　　处：《Journal of Environmental Sciences》2015年第5期240-247,共8页环境科学学报（英文版）

基　　金：supported by the Ministry of Science and Technology of China (No. 2010CB732304);the Science and Technology Department of Zhejiang Province Project (No. 2011C31010);the National Natural Science Foundation of China (No. 51202126)

摘　　要：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 Mn Ox-Nb Ox-CeO2 catalyst shows excellent low temperature NH3-SCR activity in the temperature range of 150-300℃. 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.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 Mn Ox-Nb Ox-CeO2 catalyst shows excellent low temperature NH3-SCR activity in the temperature range of 150-300℃. 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.

关 键 词：Water effect MnOx-NbOx-CeO2 catalysts Acid sites Fast SCR reaction NO/NO2 ratio 

分 类 号：X701[环境科学与工程—环境工程] O643.36[理学—物理化学]