IN-SITU MOSSBAUER STUDY OF IRON-CONTAINING MFI FERRISILICATES - RELATIONS TO CATALYTIC PROPERTIES

Ferrisilicates of MFI structure (HZSM-5) with Si/Fe ratios of 27.5, 35 and 67 have been studied by in situ Mossbauer spectroscopy, and the r esults are correlated with studies on catalytic conversions of toluene . Various species of iron ions are identified from 300 K spectra recor ded after combinations of evacuation and reduction at 570 and 670 K, r espectively. The roles of identified species are suggested in catalyti c processes.