Rapid and facile synthesis of hierarchical nanocrystalline SSZ-13 via the interzeolite transformation of ZSM-5

Abstract

Hierarchical SSZ-13 was successfully synthesized via the interzeolite conversion of ZSM-5 with high framework density (FD = 18.4 T/1000 ų) in the presence of N,N,N-trimethyl-1-adamantanamine hydroxide (TMAdaOH) under hydrothermal conditions. Compared with conventional SSZ-13, SSZ-13 derived from the interzeolite conversion of ZSM-5 possessed many merits, such as a shorter crystallization time (only 4 h), high crystallinity, high yield (73–77%), hierarchical pores, and smaller crystal size (800 nm). XRD, SEM and N₂ adsorption–desorption were used to trace the crystallization process, which allowed us to propose the synthesis mechanism of converting ZSM-5 to SSZ-13. Meanwhile, the interzeolite conversion mechanism was presumed to be that the secondary structural unit of ZSM-5 was decomposed through alkali solution treatment, and the multi-membered rings were destroyed, further reassembling into SSZ-13 under the guidance of the template. This is an alternative strategy for synthesizing a hierarchical SSZ-13 zeolite.