Cu-SSZ-13分子筛氮氧化物SCR催化机理的研究进展

Progress in Mechanism of Selective Catalytic Reduction of NOx Over Cu-SSZ-13 Zeolite

Cu-SSZ-13分子筛对于氮氧化物(NOx)具有优异的选择性催化还原(SCR)活性,其使用温度窗口宽(200~500℃)、高N2选择性和水热稳定性,可应用于移动源或者固定源的尾气脱硝。然而Cu-SSZ-13分子筛的SCR催化反应机理非常复杂,相关研究进展缓慢,例如对于Cu催化位点的认识还不够全面且有争议。鉴于此,系统阐述并讨论了Cu-SSZ-13分子筛氮氧化物SCR催化机理的研究进展,着重介绍了Cu-SSZ-13分子筛中Cu位点的种类和在结构中的分布以及各自在SCR条件下所参与的化学反应,并对目前一些争议的结论进行归纳分析,以期为此类催化剂的设计提供参考。

Cu-SSZ-13 zeolite possesses excellent selective catalytic reduction(SCR)of NOx performance under a wide operating temperature range from 200 to 500℃,high N2 selectivity and high hydrothermal stability,can be applied to reducing NOx in the exhaust of mobile and stationary sources.However,the SCR mechanism of Cu-SSZ-13 zeolite is very complicated and the related research progress is slow.For example,the active Cu sites in Cu-SSZ-13 are not fully understood and debatable.On this account,the NOx-SCR mechanism of Cu-SSZ-13 zeolite are summarized and discussed,and the Cu species in Cu-SSZ-13 structure,the related reactions under SCR are emphasized,and the current research debates are summarized and discussed to provide a reference for the design of the catalyst.