Nanosized CaCO₃ as Hard Template for Creation of Intracrystal Pores within Silicalite-1 Crystal

Abstract

The silicalite-1 crystal with intracrystal pores in the range of 50–100 nm was synthesized by using the nanosized CaCO 3 as a hard template. The nanosized CaCO 3 can be trapped into the silicalite-1 crystal during the crystallization process. By means of acid dissolution, the encapsulated nanoparticles were removed, giving rise to the intracrystal pores within the zeolite crystal. Characterization techniques including XRD, TEM, SEM, and N 2 adsorption provided the detailed information on this hierarchical pore structure. The hydroxyl groups on the surface of CaCO 3 are essential to taking the hard template effect. The secondary pores within zeolite correspond well to the morphology of the nanosized CaCO 3, which confirms the template effect of nanosized CaCO 3 . These results suggest that using CaCO 3 as a hard template may be a useful approach for the synthesis of hierarchical porous materials.