Incorporation of fluoride in as-made zeolites: New developments and applications
Résumé
The possibility to reversibly introduce fluoride species in the structure of zeolites in the presence of templating molecules has recently opened new opportunities in the preparation of materials with specific properties and in the characterization of substituted frameworks. The presentation will give an overview of the possibilities offered by this new concept, from the possibility to tune the hydrophobic/hydrophilic character of all-silica zeolites to the detailed description of Ge species in zeolite frameworks. In particular, we shall show that silicalite-1 nanocrystals (ca. 150 nm) can be obtained with a density of framework connectivity defects similar to those obtained on large crystals obtained in fluoride media. Moreover, for germanosilicates, incorporated fluoride species will be used as a NMR probe to evaluate the population, distribution and evolution of Ge atoms in the framework, particularly in the small D4R units of ITQ-17 and ITQ-24.