Directing Highly <i>a</i>-Axis-Oriented ZSM-5 Nanosheets with Pre-estimated Bifunctional Imidazole Cations
Rusi Peng, Shiqing Li, Zheng Wan, Zhi-Qiang Wang, Xiaomeng Si, Jie Tuo, Hao Xu, Yejun Guan, Jingang Jiang, Yanhang Ma, Xiao He, Xue‐Qing Gong, Peng Wu
Abstract
An MFI -topology nanosheet zeolite with a highly a -axis-oriented structure has rarely been reported but with a great potential for industrial applications. Theoretical calculations on the interaction energies between the MFI skeleton and ionic liquid molecules indicated the possibility of preferential crystal growth along a specific direction, according to which highly a -oriented ZSM-5 nanosheets were synthesized from commercially available 1-(2-hydroxyethyl)-3-methylimidazolium and layered silicate sources. The imidazolium molecules directed the structure formation and meanwhile acted as zeolite growth modifiers to restrict the crystal growth perpendicular to the MFI bc plane, which induced unique a -axis-orientated thin sheets with ∼12 nm thickness. The a -oriented ZSM-5 exhibited more competitive propylene selectivity and longer lifetime than bulky crystals in methanol-to-propylene (MTP) reaction. This research would provide a versatile protocol for the rational design and synthesis of shape-selective zeolite catalysts with promising applications.