Microcalorimetric characterization of structural and chemical heterogeneity of superacid SO4/ZrO2 systems

V. Bolis, G. Magnacca, G. Cerrato, C. Morterra

Risultato della ricerca: Contributo su rivistaArticolo in rivistapeer review

Abstract

The population of coordinatively unsaturated (eus) Zr4+ ions acting as strong Lewis acid sites on superacid sulfated zirconia catalysts, as well as the relevant heats of adsorption, were measured by means of CO adsorption at 303 K. The presence of charge-withdrawing SO4 groups slightly enhances the electron-accepting ability of the residual free surface cations, not involved in sulfate/metal complexes. H2O adsorbed at 303 K by a stepwise procedure progressively eliminates the Lewis acidic sites, through a mechanism that suggests a competition in strongly binding H2O between cus Zr4+ cations and SO4 groups. Quantitative and energetic data are reported and correlated to IR spectroscopic and catalytic data previously reported on the same catalysts. A model for the catalytic active site is proposed, based on the assumption that a strict cooperation between Lewis and Brønsted acidic sites is likely to exist.

Lingua originaleInglese
pagine (da-a)888-894
Numero di pagine7
RivistaLangmuir
Volume13
Numero di pubblicazione5
DOI
Stato di pubblicazionePubblicato - 5 mar 1997
Pubblicato esternamente

Fingerprint

Entra nei temi di ricerca di 'Microcalorimetric characterization of structural and chemical heterogeneity of superacid SO4/ZrO2 systems'. Insieme formano una fingerprint unica.

Cita questo