High Ethylene Selectivity in Methanol-to-Olefin (MTO) Reaction over MOR-Zeolite Nanosheets

Precisely controlled crystal growth endows zeolites with special textural and catalytic properties. A nanosheet mordenite zeolite with a thickness of ca. 11 nm, named as MOR-NS, has been prepared using a well-designed gemini-type amphiphilic surfactant as bifunctional structure-directing agent (SDA). Its benzyl diquarternary ammonium cations structurally directed the formation of MOR topology, whereas the long and hydrophobic hexadecyl tailing group prevented the extensive crystal growth along b axis. This kind of orientated crystallization took place through the inorganic–organic interaction between silica species and SDA molecules present in the whole process. The thin MOR nanosheets, with highly exposed (010) planes and 8-membered ring (MR) windows, exhibited a much improved ethylene selectivity (42.1 %) for methanol-to-olefin (MTO) reactions when compared with conventional bulk MOR crystals (3.3 %).