Characterization of mesoporous materials by vibrational spectroscopic techniques

Vibrational spectroscopic techniques (i.e. infrared, Raman-spectroscopy and inelastic neutron scattering) are employed for the characterization of the wall structure and the nature of active sites in ordered mesoporous MCM-41 materials. Supported by nitrogen physisorption measurements our results provide unambiguous evidence for the destruction of mesoporous pore structures under a pressure usually used for the preparation of wafers for transmission IR spectroscopy. Avoiding pressure treatment of the samples, vibrational spectroscopic studies are suited to yield information about the effects of isomorphous substitution and calcination on the framework structure of mesoporous materials. The utilization of O-18 isotope labelling and N-methylpyrrolidinc adsorption revealed the heterogeneity of hydroxyl groups in MCM-41 materials. (C) 2003 Elsevier Inc. All rights reserved.