Catalysis Letters

, Volume 42, Issue 1, pp 25–33

Infrared studies of the interaction of carbon monoxide and dinitrogen with ferrisilicate MFI-type zeolites

  • A. Zecchina
  • F. Geobaldo
  • C. Lamberti
  • S. Bordiga
  • G. Turnes Palomino
  • C. Otero Areán
Article

DOI: 10.1007/BF00814463

Cite this article as:
Zecchina, A., Geobaldo, F., Lamberti, C. et al. Catal Lett (1996) 42: 25. doi:10.1007/BF00814463

Abstract

Fourier transform IR spectroscopy of CO and N2, adsorbed at liquid nitrogen temperature, was used to characterize an MFI-type H-FeZSM-5 ferrisilicate which was synthesized with a Si/Fe ratio of 50. Thermal treatment of this material at 773 and 973 K was performed in order to follow formation of extraframework species. On samples fired at 773 K Brønsted acid sites were present which gave an O-H stretching band at 3630 cm−1. These hydroxyl groups formed adducts with both probe molecules, which were monitored by the corresponding bathochromic shift, Δν. Corresponding values for adsorbed CO and N2 were Δν = −270 and Δν = − 100, respectively. Increasing the firing temperature up to 973 K led to complete removal of iron from the zeolite framework, and consequent disappearance of Brønsted acidity. In this process, extraframework iron oxide species were formed which were also characterized by IR spectroscopy of the adsorbed probe molecules. Both CO and N2 gave Lewis-type adducts with coordinatively unsaturated Fe3+ ions present in the extraframework material. A comparison is made with results of a previous study on the H-GaZSM-5 isomorph.

Keywords

zeolites ferrisilicate H-FeZSM-5 CO adsorption dinitrogen adsorption IR spectroscopy 

Copyright information

© J.C. Baltzer AG, Science Publishers 1996

Authors and Affiliations

  • A. Zecchina
    • 1
  • F. Geobaldo
    • 1
  • C. Lamberti
    • 1
  • S. Bordiga
    • 1
  • G. Turnes Palomino
    • 3
  • C. Otero Areán
    • 3
  1. 1.Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei MaterialiUniversità di TorinoTurinItaly
  2. 2.Departamento de QuímicaUniversidad de las Islas BalearesPalma de MallorcaSpain
  3. 3.Dipartimento di Scienza dei Materiali e Ingegneria ChimicaPolitecnico di TorinoTurinItaly

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