Preparation and Characterization of Fe-containing Mesoporous HZSM-5 Catalysts for Automotive Exhaust Cleaning

Abstract

Mesoporous HZSM-5was prepared by alkali solution treating microporous HZSM-5, then Fe/ZSM-5 catalysts have been successfully fabricated by equal volume impregnation method. Their texture structure, crystal phase structure and acidity were characterized by N2 physisorption /desorption, XRD, SEM and NH3-TPD techniques. The results show that mesoporous surface area and mesoporous pore volume of the ZSM-5 after alkali treatment increased obviously from 77m 2 /g and 0.086cm 3 /g to 192m 2 /g and 0.326cm 3 /g respectively. XRD patterns show the crystallinity of the zeolite treated by alkali decreased gradually with the increase of alkali concentration. The XRD patterns of the FeCl3/ZSM-5 samples show that the high FeCl3 dispersion in the zeolites treated by alkali. All zeolites have the MFI framework topology. When Fe-ZSM-5 is used as catalyst for cleaning auto-exhaust, the catalytic effect of mesoporous molecular sieve loaded with FeCl3 is more active than HZSM-5.