The dehydration and rehydration of a catalytically active (superacid) sulfate-doped ZrO2 system has been studied by IR spectroscopy. By the adsorption of pyridine, the acidity of the system has been tested in various stages of the dehydration/rehydration process. Brønsted acid centers are abundantly present and are in different hydraticn states after dehydration at temperatures in the 300-473 K interval. For dehydration at T ≥ 473 (but not higher than ≈900 K), declining amounts of acid protonic centers are still present and are in an anhydrous form; the original Brønsted acidity can be regenerated upon rehydration at ambient temperature. © 1994 American Chemical Society.
Brønsted acidity of a superacid sulfate-doped ZrO2 system
PINNA, Francesco;SIGNORETTO, Michela
1994-01-01
Abstract
The dehydration and rehydration of a catalytically active (superacid) sulfate-doped ZrO2 system has been studied by IR spectroscopy. By the adsorption of pyridine, the acidity of the system has been tested in various stages of the dehydration/rehydration process. Brønsted acid centers are abundantly present and are in different hydraticn states after dehydration at temperatures in the 300-473 K interval. For dehydration at T ≥ 473 (but not higher than ≈900 K), declining amounts of acid protonic centers are still present and are in an anhydrous form; the original Brønsted acidity can be regenerated upon rehydration at ambient temperature. © 1994 American Chemical Society.
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