Tuning the NOx conversion of Cu-Fe/ZSM-5 catalyst in NH3-SCR

Abstract Cu-Fe/ZSM-5 catalyst prepared by subsequent ion-exchange showed higher NOx conversion compared with Fe/ZSM-5 or Cu/ZSM-5. Presence of small amount of copper in xCu-yFe/ZSM-5 catalysts was found to be enough to improve the low temperature NOx conversion without significantly affecting the high temperature performance. Co-presence of Cu increases the reducibility of Fe and also increased strong acid sites in Cu-Fe/ZSM-5. However, no correlation between acid site strength and NOx conversion is observed. Higher NOx conversion over Cu-Fe/ZSM-5 can be correlated to the facile reduction of metal species. Thus the redox properties and NOx conversion can be tuned by changing the composition of Cu-Fe/ZSM-5 catalyst.