J. Phys. IV France 7 (1997) C2-851-C2-853
XAFS, IR, Raman and UV-Vis Characterization of Framework Ti(IV) Species in Ti-SilicalitesC. Lamberti1, S. Bordiga1, A. Zecchina1, G. Vlaic2, G. Tozzola3, G. Petrini3 and A. Carati4
1 Dipartimento di Chimica I.F.M., Via P. Giuria 7, 10125 Torino, Italy
2 Dipartimento di Scienze Chimiche e Sincrotrone Trieste SCpA, Trieste, Italy
3 ENICHEM SpA, Centro di Ricerche di Novara, Via G. Fauser 4, Novara, Italy
4 ENI RICERCHE, Via F. Maritano 26, 20097 S. Donato (Mi), Italy
The main results obtained by using IR, Raman and UV-Vis techniques concerning the structure of the Ti(IV) center in Ti-silicalite is briefly reviewed and discussed with recent XAFS results. The Ti(IV) is in tetrahedral coordination in vacuo and expands its coordination sphere upon interaction with adsorbates. Present EXAFS results indicate, for the dehydrated sample, a first shell coordination number higher then four (4.45 ± 0.3), suggesting, in a fraction of sites, the substitution of a bridged oxygen with two OH groups.
© EDP Sciences 1997