Intergrowth\nMFI Zeolite with Inverse Al Zoning and\nPredominant Sinusoidal Channels for Highly Selective Production of\nStyrene

ZSM-5 zeolites with accessible micropore architecture\nand tunable\nacid–base sites are important shape-selective catalysts. However,\nthe presence of exposed straight channels and the external acid–base\nsites of conventional ZSM-5 has a negative impact on shape selectivity.\nHerein, we report on the direct synthesis of an intergrowth ZSM-5\nzeolite mimicking the mortise–tenon joints. It can be revealed\nby various methods that the mortise–tenon ZSM-5 shows an inverse\nAl gradient from the surface to the core of the zeolite. More importantly,\nthe sinusoidal channels predominantly opened to their external surfaces\nare constructed. The shape-selective capability of the ZSM-5 zeolite\nhas been fully exploited due to the intrinsic inert external surface\nand unique sinusoidal channel features, thereby resulting in high\nstyrene selectivity (>90%) and good catalytic stability (>100\nh) in\nthe toluene side-chain alkylation reaction. In addition, in situ DRIFTS\nconfirms that this intergrowth ZSM-5 contributes to the formation\nof more active intermediates of HCOO* and H<sub>3</sub>CO*, which\nis another reason responsible for the superior performance.