Synthesis of multilamellar ZSM-5 nanosheets with tailored b-axis thickness

The ZSM-5 zeolite nanosheets are highly desired materials for catalytic reactions and membrane separation. Their synthesis depends on specially designed complex surfactants; however, the high-cost limits their large-scale industrial production. Herein, the tailored synthesis of coffin-shaped multilamellar ZSM-5 composed of orderly stacked 2D nanosheets is carried out using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent (SDA) in the presence of silicalite-1 seed sol. The morphology and b-axis thickness of nanosheets is controlled by adjusting the amount of silicalite-1 seed sol, CTAB/TEOS ratio, SiO2/Al2O3 ratio, and synthesis time. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis indicate that the hydrophobic tail of CTAB acts as an inhibitor, effectively preventing the continuous growth along b-direction with an average thickness of 20-100 nm. This work highlights the role of silicalite-1 seed sol and CTAB in the orderly stacked sheets growth process. This crystallization strategy opens a facile and inexpensive approach for multilamellar ZSM-5 zeolite fabrication with 2D-nanosheets structures, and their practical applications in catalytic conversions of bulky molecules.

Automated summary

This study demonstrates a tailored synthesis of multilamellar ZSM-5 zeolite composed of orderly stacked 2D nanosheets using silicalite-1 seed sol and CTAB. The hydrophobic tail of CTAB acts as an inhibitor to control the growth of nanosheets. This crystallization strategy offers a facile and inexpensive approach for fabricating multilamellar ZSM-5 zeolite with 2D-nanosheets structures.