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

Abstract

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, H₂-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.