Multi-modal porous Faujasite particles assembled from primary zeolite NaY nanocrystals were hydrothermally synthesized using a three-stage variable- temperature program without adding any organic templates and seeding crystals. The powder X-ray diffraction (XRD) patterns of the synthesized samples showed the diffraction peaks associated with zeolite FAU structure were significantly broadened, indicating the primary stacking crystals were very small. Scanning electron microscopy (SEM) images showed that the zeolite particles are composed of very uniform zeolite NaY nanocrystals in the size range of 20-80 nm. Transmission electron microscopy (TEM) images revealed the partial intergrowth and random packing characteristics of the primary zeolite NaY nanocrystals. FAU structure of the synthesized samples was further confirmed by Fourier transform infrared (FT-IR) results. Interestingly, the particle sizes of the porous zeolites could be easily controlled by varying the alkalinity of the precursor without notably changing the primary sizes of zeolite NaY nanocrystals. N2 adsorption results showed the zeolite particles contained disordered micro- and mesopores and had large surface area arising from zeolite NaY nanocrystals. The hierarchical porous particles are mechanically strong, and they remain intact after ultrasonication for several hours.
|Title of host publication||Engineers Australia|
|Publication status||Published - 27 Sep 2009|