SAXS/WAXS investigations into the self-assembly of zeolites

Zeolites are materials with monodisperse pores and well-defined active sites, 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 extremely scarce. This is mainly due to experimental difficulties, which we have solved by performing simultaneous small- and wide- angle X-ray scattering (SAXS/WAXS) during the in-situ preparation of zeolites in a dedicated, rotating 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 process, covering extended length scales. Based on a broad range of zeolite crystallizations, an assembly mechanism has been proposed which is probably general for organic-mediated zeolite synthesi