Synthesis of nano-ZSM-5 zeolite via a dry gel conversion crystallization process and its application in MTO reaction

In this work, nano-ZSM-5 zeolite with superior catalytic properties was synthesized from LAPONITE (R) as one of the Si sources by a dry gel conversion (DGC) method, and its crystallization mechanism was investigated as well. The properties of ZSM-5(Z-L) synthesized from LAPONITE (R) as one of the Si sources and ZSM-5(Z-T) synthesized from tetraethylorthosilicate (TEOS) as a single Si source have been compared. The results show that LAPONITE (R) is an important factor for the formation of nanocrystals with high crystallinity. It can not only act as the Mg and Si source for the zeolite synthesis but also exert a "confined space" effect to control ZSM-5 crystal growth. The Z-L sample with nanosized crystals can shorten the reactant and product diffusion path length, which seriously improves diffusion efficiency and results in longer catalytic stability. This work provides a novel and efficient route for synthesis of nano-ZSM-5 zeolite.