One-step dual template synthesis of hybrid lamellar-bulk MFI zeolite

Abstract

A one-step dual template strategy was employed to achieve the facile synthesis of hybrid lamellar-bulk MFI (HLBM) zeolite, consisting of a lamellar zeolite structure on the surface of the bulk zeolite core. Tetrapropyl ammonium hydroxide (TPAOH) and diquarternary ammonium surfactant ([C₂₂H₄₅–N⁺(CH₃)₂–C₆H₁₂–N⁺(CH₃)₂–C₆H₁₃]Br₂, C_22-6-6) with a composition of 100SiO₂/xC_22-6-6/36TPAOH/4000H₂O was used as the template in the HLBM zeolite synthesis. The influences of several parameters on the HLBM zeolite formation were investigated, including concentration of C_22-6-6, hydrothermal synthesis time, and ageing temperature and time prior to hydrothermal crystallization. The sizes of lamellar and bulk domains of the HLBM zeolite and thus its meso- and micro-porosity can be modulated by simply tuning these parameters. A possible growth scheme of the HLBM zeolite is discussed. The ability to form hybrid zeolite particles with tunable meso-/micro-porosity is important to keep their potential application as broad as possible for specific zeolite structures. The dual template synthesis approach presented is potentially applicable to form other types of hybrid lamellar-bulk zeolite materials.