Preparation of Hierarchical Porous and Tunable Silicon Microenvironment SAPO-18 Sheets for Methanol-to-Olefins

In this study, hierarchically porous SAPO-18 catalysts with abundant intracrystalline mesopores were designed and fabricated with a cost-effective non-surfactant cationic surfactant (polydimethyldiallylammonium chloride, PDADMAC) as a pore-forming agent, morphology regulator, and silicon inducer by a one-step method. PDADMAC promoted the introduction of silicon atoms in the SAPO-18 framework, making the hierarchical porous SAPO-18 sheets present abundant optimized acidity. With the combination of porous structure and suitable acid density, the hierarchical porous SAPO-18 sheets exhibited a threefold improvement in catalytic lifetime and a 4% increase in ethylene and propylene selectivity during the methanol-to-olefin (MTO) reaction, compared with the conventional SAPO-18 zeolite.