Directing Highly a-Axis-Oriented ZSM-5 Nanosheets with Pre-estimated Bifunctional Imidazole Cations

An MFI-topology nanosheet zeolite with ahighly a-axis-oriented structure has rarely beenreported but witha great potential for industrial applications. Theoretical calculationson the interaction energies between the MFI skeletonand ionic liquid molecules indicated the possibility of preferentialcrystal growth along a specific direction, according to which highly a-oriented ZSM-5 nanosheets were synthesized from commerciallyavailable 1-(2-hydroxyethyl)-3-methylimidazolium and layered silicatesources. The imidazolium molecules directed the structure formationand meanwhile acted as zeolite growth modifiers to restrict the crystalgrowth perpendicular to the MFI bc plane,which induced unique a-axis-orientated thin sheetswith similar to 12 nm thickness. The a-oriented ZSM-5exhibited more competitive propylene selectivity and longer lifetimethan bulky crystals in methanol-to-propylene (MTP) reaction. Thisresearch would provide a versatile protocol for the rational designand synthesis of shape-selective zeolite catalysts with promisingapplications.

Automated summary

A highly a-axis-oriented nanosheet zeolite with great industrial applications potential was synthesized using ionic liquid molecules and layered silicate sources. The resulting a-oriented ZSM-5 showed enhanced propylene selectivity and longer lifetime in the methanol-to-propylene reaction compared to bulky crystals. This research provides a versatile protocol for designing and synthesizing shape-selective zeolite catalysts with promising applications.