Crystal Seed-Assisted Synthesis of ZSM-5 Zeolite Nanosheets

Conventional ZSM-5 zeolites exhibit limited efficiency in converting macromolecular reactants due to diffusion constraints arising from their narrow microporous structure. In this work, a strategy combining precrystallized seeds and diquaternary ammonium templates was developed, which enabled the fast synthesis (3 days) of ZSM-5 nanosheets with a thickness of approximately 2 nm. This method reduced the synthesis time by 57% compared with conventional approaches (7 days). During the catalytic cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), the nanosheet zeolites achieved a conversion of 67.2%, representing a 7-fold enhancement over conventional ZSM-5 (9.2%). In situ DRIFTS characterization revealed that this enhanced performance is linked to the hierarchical architecture, which shortens diffusion pathways and facilitates the rapid desorption of olefins from active sites, thereby suppressing coke formation. These findings highlight the potential of this approach for advancing heavy oil catalytic cracking processes.