Aluminium triplets in dealuminated zeolites detected by Al-27 NMR correlation spectroscopy
Résumé
Arrangements associating three aluminium atoms in dealuminated Y zeolites are for the first time detected using a combination of multiple-quantum MAS (MQMAS) and 2D double-quantum homonuclear NMR correlation spectroscopy. From these results, we propose a model describing the enhanced Bronsted acid sites in dealuminated Y zeolite, consisting in a configuration where framework aluminium pairs are interacting with cationic extra-framework aluminium atoms. (C) 2009 Elsevier Inc. All rights reserved.