Organic template-free synthesis of zeolite mordenite nanocrystals through exotic seed-assisted conversion

Abstract

Seed-assisted synthesis has been demonstrated as a green and facile route to produce useful zeolites with several frameworks, and meanwhile shows the potential to selectively template the formation of specific structured crystals. In view of the difficulty of directly synthesizing zeolite mordenite (MOR) with short 1D, 12-MR channels, we proposed a plausible synthetic route of exotic seed-assisted conversion (ESAC), starting from aluminosilicate gel containing zeolite beta (BEA) seeds to MOR nanocrystals. Through judiciously adjusting the synthetic conditions, including NaF/Si, OH⁻/Si, hydrothermal temperature and added zeolite BEA seeds, nano-crystallite assembled zeolite MOR nanoparticles with rich inter-crystallite mesoporosity, high crystallinity, perfect framework, and high catalytic activity for low-density polyethylene cracking, were fast transformed under a low seeded, organic template-free system. The combined investigation of synthetic conditions and the crystallization process deepened the understanding on this special crystallization behaviour.