Synthesis of hierarchical porous zeolite NaY particles with controllable particle sizes

Hierarchical porous particles aggregated from primary zeolite NaY nanocrystals were hydrothermally synthesized via a three-stage temperature control strategy, without adding any organic additives. The as-synthesized samples were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), N2 sorption, particle size analysis and Fourier Transform Infrared (FT-IR) spectroscopy. The results show that the zeolite aggregate particles with sizes of 190–600 nm are composed of highly crystalline zeolite NaY nanoparticles in the size range of 20–80 nm. The particle sizes of hierarchical porous aggregates can be readily tuned by varying the alkalinity of the zeolite precursor gel without notably changing the sizes of the primary zeolite nanocrystals. N2 sorption results show that zeolite NaY aggregate particles have microporosity and mesoporosity (30.8–57.6%). The hierarchical zeolite particles exhibit very good mechanical stability, and remain intact after ultrasonication for several hours.