One-Step Dual Template Mediated Synthesis of Nanocrystalline Zeolites of Different Framework Structures

Abstract

A novel, dual template mediated, one-step direct synthesis route is reported here for the preparation of nanocrystalline zeolites of different framework structures (such as ZSM-5, mordenite, and sodalite). In this synthesis strategy, a suitably designed dicationic/tetra-cationic soft template was used along with a conventional zeolite structure director to obtain nanocrystalline zeolites with nanosheet morphology. Nanocrystalline zeolites exhibited large surface area, pore volume, and intercrystalline mesopores. The long hydrophobic chain containing a multiammonium template cooperatively participates in the zeolite crystallization process along with a conventional microporous zeolite structure director to form the ultrathin microporous zeolite framework, while the hydrophobic interaction between the long chains restricted the excessive growth of zeolites and induced the formation of intercrystalline mesopores. Nanocrystalline zeolites exhibited exceptionally high activity in the acid-catalyzed reactions i...