Sphere-like Hierarchical Y Zeolite Fabricated by Steam-assisted Conversion Method

Sphere-like hierarchical Y zeolite was synthesized by a "steam-assisted conversion (SAC)" procedure.The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption, solid-state nuclear magnetic resonance (NMR) spectra, and Fourier transform infrared (IR) spectroscopy.Results observed by SEM displayed that the as-synthesized Y zeolite was sphere-like polycrystalline aggregates composed of primary crystals with size of about 50-300 nm.These results exhibited that some polycrystalline aggregates were hollow Y zeolite spheres.Combined with characterization results of FT-IR, 29 Si NMR, SEM, and TEM, a mechanism illustrating formation of the hollow Y zeolite polycrystalline spheres was proposed.