Different types of cationic species acting as Lewis acid sites as well as Na-counter ion in dealuminated zeolites are investigated, for the first time, using periodic density functional method. The energy of ammonia adsorption is taken as a measure for the acidity. The results reveal that the relative strength of the investigated active sites increases in the order: Na + < Al(OH) 2 + < AlO + < Si + . Moreover, the interaction of NH 3 with tri-coordinated aluminum dislodged in the framework is less favorable than that with the neighboring silicon ion.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films