Role of aggregated Fe oxo species in N2O decomposition over Fe/ZSM-5

摘要

The effects of aggregated Fe oxo (FeOx) species on N2O decomposition activity of aqueous ion-exchanged Fe/ZSM-5 were investigated. Aggregation of FeOx species was achieved by thermal treatment of the Fe/ZSM-5 catalysts at different temperatures (600-900 degrees C) in pure Ar. The characterizations were carried out using X-ray diffraction, N-2 physisorption, UV-Vis diffuse reflectance spectroscopy, X-ray absorption fine structure spectroscopy, pulse-response analysis, and O-2-temperature-programmed desorption. The FeOx species on the external framework of the ZMS-5 zeolite played a dominant role in N2O decomposition over Fe/ZSM-5. By studying the relationship between the contents of the various existing iron species and activity of the different catalysts, polynuclear FeOx appeared to be the main active phase for N2O decomposition. Additionally, Fe-O with a long bond length ((Fe-O)(2)) in amorphous polynuclear FeOx was positively correlated to the activity of the catalysts, indicating that (Fe-O)(2) was the active species for N2O decomposition. (C) 2014, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.