SAXS/WAXS investigations into the self-assembly of zeolites

Zeolites are materials with monodisperse pores and well-defined active site s, and are therefore especially suitable for tailor-made applications such as selective catalysts or adsorbents for specific systems. Knowledge of the fundamental processes during the preparation of zeolites is still extremel y scarce. This is mainly due to experimental difficulties, which we have so lved by performing simultaneous small- and wide- angle X-ray scattering (SA XS/WAXS) during the in-situ preparation of zeolites in a dedicated, rotatin g heating cell at Station 8.2 of the SRS at Daresbury Laboratory. Using in- situ SAXS/WAXS, for the first time the nanometer-scale precursors during a zeolite synthesis have been identified, and their formation and consumption have been monitored during the complete course of the crystallization proc ess, covering extended length scales. Based on a broad range of zeolite cry stallizations, an assembly mechanism has been proposed which is probably ge neral for organic-mediated zeolite synthesis.