Interzeolite conversion of HY to hierarchical HZSM-5 catalyst via an ionothermal route and its excellent catalytic performance in methanol-to-aromatics reaction

Currently, synthesizing zeolites with specific physicochemical properties in a more environmentally benign and safe way is challenging. Herein we report a novel ionothermal route of preparing HZSM-5 zeolite, which is featured by the direct interzeolite transformation of HY to HZSM-5. The appropriate synthetic conditions of this HZSM-5 material are refined. Although performing a series of optimization, the resultant product still contains minor (NH 4 ) 3 AlF 6 impurity. Pure HZSM-5 phase with high relative crystallinity can be obtained through successive calcination and acid-washing treatments towards the as-made sample. SEM–EDS characterization and nitrogen physisorption measurement reveal that this pure HZSM-5 sample is composed of classical coffin-like crystals with a low Si/Al ratio and evident hierarchical micro-mesoporous structure. Benefiting from its unique physicochemical properties, this pure HZSM-5 catalyst exhibits more superior methanol-to-aromatics performance than those of the state-of-the-art HZSM-5 and Metal/ZSM-5 catalysts evaluated under similar reaction conditions. It can be anticipated that this HZSM-5 material may be applied in other industrially relevant reactions owing to its particular structure and properties.