Exploring the internal structure of mesoporous powders and thin films by continuous flow laser-enhanced 129Xe NMR.
Résumé
Continuously circulating flow of laser hyperpolarized (HP) 129Xe NMR technique has been used to study the porous structure of ordered purely siliceous MCM-41, SBA-15 mesoporous materials and mesoporous SiO2 and TiO2 thin films. The use of hyperpolarized xenon allows us to measure spectra at very low concn. of xenon where xenon reflects mainly interaction between the adsorbed xenon atoms and the surface. Variable temp. measurements allowed us to obtain information on the heat of adsorption of xenon on the surface and to evaluate the chem. shift of xenon in interaction with the surface.