Species active in the selective catalytic reduction of no with iso-butane on iron-exchanged ZSM-5 zeolites
AUTOR(ES)
Batista, M. S., Wallau, M., Urquieta-González, E. A.
FONTE
Brazilian Journal of Chemical Engineering
DATA DE PUBLICAÇÃO
2005-09
RESUMO
Fe-ZSM-5 catalysts were prepared by ion exchange in aqueous medium or in the solid state and tested in the catalytic reduction of NO with iso-butane. X-ray powder diffraction (XRD), atomic absorption spectroscopy (AAS), electron paramagnetic resonance spectroscopy (EPR), X-ray absorption spectroscopy (XANES, EXAFS), temperature-programmed reduction by H2 (H2-TPR) and Mössbauer spectroscopy (MÖS-S) were used for sample characterisation. Irrespective of the method used in catalyst preparation, EPR, XANES and MÖS-S showed Fe atoms in the oxidation state of 3+. MÖS-S and H2-TPR data on Fe-ZSM-5 prepared by ion exchange in the solid state allowed quantification of a lower hematite (Fe2O3) concentration and a higher proportion of Fe cations than samples prepared in an aqueous medium. In all the catalysts studied these Fe cations were the active sites in the reduction of NO to N2 and in the oxidation of iso-butane. It is further suggested that coordination of Fe species is another important aspect to be considered in their behaviour.
Documentos Relacionados
- Selective catalytic reduction of NO to N2 with copper and cobalt exchanged ZSM-5 zeolites: the effect of calcium addition
- Cu and Co exchanged ZSM-5 zeolites: activity towards no reduction and hydrocarbon oxidation
- Desilication of ZSM-5 and ZSM-12 Zeolites with Different Crystal Sizes: Effect on Acidity and Mesoporous Initiation
- SYNTHESIS AND CHARACTERIZATION OF NANOCRYSTALLINE MORDENITE, FERRIERITE AND ZSM-5 ZEOLITES
- Polymerization of Ethylene with Zirconocene Heterogenized on Spherical ZSM-5