Spectroscopic tools for probing the isolated titanium centres in MCM41 mesoporous catalysts

Catalytically active Ti(IV) centres anchored to the inner walls of MCM-41 mesoporous silicas have been investigated using a combination of FT-IR, diffuse reflectance UV-visible and luminescence spectroscopy supplemented by the use of H20 and NH3 as molecular probes of the Ti coordination. The results re-affirm and extend the conclusions reported earlier for the Ti-MCM41 novel epoxidation catalysts, see MASCHMEYER T., REY F., SANKAR G. and THOMAS J. M., Nature, 378 (1995) 159, who, using in situ EXAFS studies, showed that the Ti(IV) centres exist largely as isolated active sites.