Extraframework cation sites in the sodium forms of the zeolites ZSM-5, mordenite, Linde-4A and faujasite-type X and Y have been investigated by using low-temperature adsorption of dihydrogen and carbon monoxide as IR spectroscopic probes. The extent of H-H and C-O bond polarization was found to be dependent not only on the cation electrostatic field, but also on the neighbouring oxygen atoms of the zeolite framework. The influence of these oxygen atoms is most keenly felt by adsorbed molecular hydrogen, but they also affect the IR frequency shift of the stretching vibration of adsorbed carbon monoxide. The Si : Al ratio of the zeolite framework modulates the basic strength of the oxygen atoms, and this was found to be reflected in the IR stretching frequency of both adsorbed molecules, H2 and CO.
Comparative IR Spectroscopy Study of Low-Temperature H2 and CO adsorption on Na-Zeolites / S. Bordiga; E. Garrone; C. Lamberti; A. Zecchina; C. Otero Areán; V.B. Kazansky; L.M. Kustov. - In: JOURNAL OF THE CHEMICAL SOCIETY. FARADAY TRANSACTIONS. - ISSN 0956-5000. - 90(1994), pp. 3367-3372.
Titolo: | Comparative IR Spectroscopy Study of Low-Temperature H2 and CO adsorption on Na-Zeolites |
Autori Riconosciuti: | |
Autori: | S. Bordiga; E. Garrone; C. Lamberti; A. Zecchina; C. Otero Areán; V.B. Kazansky; L.M. Kustov |
Data di pubblicazione: | 1994 |
Abstract: | Extraframework cation sites in the sodium forms of the zeolites ZSM-5, mordenite, Linde-4A and faujasite-type X and Y have been investigated by using low-temperature adsorption of dihydrogen and carbon monoxide as IR spectroscopic probes. The extent of H-H and C-O bond polarization was found to be dependent not only on the cation electrostatic field, but also on the neighbouring oxygen atoms of the zeolite framework. The influence of these oxygen atoms is most keenly felt by adsorbed molecular hydrogen, but they also affect the IR frequency shift of the stretching vibration of adsorbed carbon monoxide. The Si : Al ratio of the zeolite framework modulates the basic strength of the oxygen atoms, and this was found to be reflected in the IR stretching frequency of both adsorbed molecules, H2 and CO. |
Volume: | 90 |
Pagina iniziale: | 3367 |
Pagina finale: | 3372 |
Digital Object Identifier (DOI): | 10.1039/ft9949003367 |
URL: | http://pubs.rsc.org/en/Content/ArticleLanding/1994/FT/ft9949003367 |
Parole Chiave: | Zeolite; Na cation; FTIR; molecular adsorption; CO; H2; surface site acidity |
Rivista: | JOURNAL OF THE CHEMICAL SOCIETY. FARADAY TRANSACTIONS |
Appare nelle tipologie: | 03A-Articolo su Rivista |
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