Oxidative dehydrogenation of propane with nitrous oxide over Fe-MFI prepared by ion-exchange: effect of acid post-treatments

Fe-MFI prepared by reductive solution ion-exchange was investigated as catalyst for the oxidative dehydrogenation of propane with nitrous oxide, and a maximal propylene yield of ca. 14% could be obtained at the reaction temperature of 673 K. Accumulative acid post-treatments were performed on Fe-MFI and a gradual increase of maximal propylene yield to ca. 25% could be observed. The Fe-MFI samples before and after acid post-treatments were characterized by means of ICP, XRD, DRIFT, TEM, UV-Vis, H-2-TPR, NH3-TPD and EPR. The results clearly indicated the transformation of iron species during acid post-treatments. The active iron species in Fe-MFI before and after acid post-treatments were characterized by FTIR spectra of NO adsorption. Based on the characterization and catalytic results, the extra-framework Fe-O-Al species and/or isolated iron species in Fe-MFI were proposed to be more active than oligonuclear iron species for propane dehydrogenation with nitrous oxide.