On the Lewis acidity of protonic zeolites

- Lewis acidity of three H-MFI and two H-Y zeolites is studied.
- Low-Al dealuminated H-Y presents some strong Lewis acidity.
- Pyridine and pivalonitrile adsorption perturb also LF OH band of dealuminated H-Y.
- Framework tetrahedral Al3+ can act as Lewis acid sites enlarging the coordination.