Performance of Fe-Cu/ZSM-5 catalyst in the DeNO_x process via NH₃-SCR

A series of Fe-Cu/ZSM-5 catalysts with different Fe/Cu molar ratios were prepared by impregnation method and characterized by XRD, H₂-TPR, NH₃-TPD and in situ DRIFTS; their performance in the denitrification (de-NO_x) process via NH₃-SCR was investigated.The results showed that the bimetallic modified Fe-Cu/ZSM-5 catalysts have a broad active temperature window.Especially, the Fe-Cu/ZSM-5 1:4 catalyst with a Fe/Cu molar ratio of 1:4 displays the highest activity; over it, the deNO_x efficiency reaches the maximum of 99.46% at 335℃ and keeps above 90% at 250-450℃.Copper and iron species, present as amorphous oxides, are finely dispersed on the catalyst surface and the bimetallic modified catalysts retain the crystal structure of ZSM-5.The Fe-Cu/ZSM-5 1:4 catalyst exhibits abundant acid sites and excellent redox performance.E-R mechanism and L-H mechanism may coexist during the NH₃-SCR reaction under certain temperature; moreover, the onset temperature of E-R mechanism is much lower than that of L-H mechanism and the denitration reaction may be ignited at 200℃.