(138b) One-Step Dual Template Synthesis of Hierarchical Layered Zeolite with Tailored Textural and Catalytic Properties
A one-step dual template strategy was employed to achieve facile synthesis of meso-/microporous layered zeolites with tailored morphology, mesoporosity and catalytic activity. Tetrapropyl ammonium hydroxide (TPAOH) and diquaternary ammonium surfactant ([C22H45-N+(CH3)2-C6H12-N+(CH3)2-C6H13]Br2, C22-6-6) with a composition of 100SiO2/xC22-6-6/yTPAOH/4000H2O were used as the templates in meso-/microporous layered zeolite synthesis. The influences of several parameters on the zeolite formation were investigated, including concentration of TPAOH and C22-6-6, hydrothermal synthesis time, and ageing temperature and time prior to hydrothermal crystallization. The sizes of mesoporous and microporous domains of the zeolite and thus its meso- and microporosity can be modulated by simply tuning these parameters. The catalytic studies showed that the catalytic activity and selectivity can be systematically modulated by varying these parameters in the synthesis. The ability to form hierarchical zeolite particles with tunable meso-/microporosity is important to keep their potential applications as broad as possible for a specific zeolite structure. The dual template synthesis approach presented is potentially applicable to form other types of meso-/microporous zeolite materials.