Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and its synergic application with Fe/Beta catalysts  

作　　者：Chen Wang Jun Wang Jianqiang Wang Meiqing Shen 

机构地区：[1]School of Chemical Engineering&Technology,Key Laboratory for Green Chemical Technology of State Education Ministry,Tianjin University,Tianjin 300072,China [2]School of Environment and Safety Engineering,North University of China,Taiyuan 030051,China

出　　处：《Frontiers of Environmental Science & Engineering》2021年第2期141-153,共13页环境科学与工程前沿（英文）

基　　金：the funding from National Key Research and Development Program of China(No.2017YFC0211302);National Natural Science Foundation for Youth of China(Grant No.21908207);China Postdoctoral Science Foundation(No.2020M670659);Shanxi Province Science Foundation for Youths(Nos.201901D211224 and 201801D221351).

摘　　要：K ions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging.The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction(SCR)activity.For the fresh Cu/SAPO-34 catalysts,K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites.After hydrothermal aging,the structural integrity and amount of active sites decreased on pure Cu/SAPO-34.While the K-loaded catalysts showed improved chabazite structure,acidity,and active site conservation with increasing K loading.However,although the 0.7 wt%K catalyst maintained the same crystallinity,active site abundance,and low-temperature SCR activity as the fresh catalyst upon aging,an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites.To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature,Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34,and a wide active temperature window of SCR activity was obtained.Thus,our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NOx in real-world applications.

关 键 词：Selective catalytic reduction Cu/SAPO-34 catalyst Ion-exchanged K Low-temperature hydrothermal stability Fe/Beta catalyst 

分 类 号：O64[理学—物理化学]