Understanding roles of Ce on hydrothermal stability of Cu-SSZ-52 catalyst for selective catalytic reduction of NOx with NH3

CexCu-SSZ-52 catalysts with SFW topology were first prepared by ion-exchange method and used to investigate the effect of Ce content on SFW framework and resistance ability of high-temperature hydrothermal aging. Among the several loadings of Ce on Cu-SSZ-52, i.e. 0.48 wt%, 0.75 wt%, 0.98 wt% and 1.0 wt%, Ce0.98Cu-SSZ52 presents the most excellent hydrothermal stability. Upon the 800 degrees C hydrothermal treatment, Ce0.98Cu-SSZ52-800 shows enhanced deNOx performance than either Ce less sample or the SSZ-13 counterpart. The XRD and 27Al MAS NMR further demonstrate the stabilization effect of Ce species on the SFW framework. Furthermore, we utilize the EPR, H2-TPR, and XPS analysis to study the change of active species. The results confirm that the addition of Ce promotes the production of active Cu2+ species and inhibits the generation of CuOx and Cu+ as the interaction between Cu and Ce species exists in Ce0.98Cu-SSZ-52-Fresh catalyst.