Regioselective Distribution of Zinc Hydroxyl within Straight Channels in MFI Zeolite Nanosheets for Propane Dehydrogenation

Direct dehydrogenation of propane (PDH) is an important industrial process to produce propylene. Transition-metal oxides encapsulated within zeolites (TM@Zeolite) are promising nonprecious and nontoxic alternatives for commercial Pt and CrOx-based PDH catalysts, and it is of great interest to further optimize the catalytic performance of TM@Zeolite. This study describes a facile dual-ligand-directed synthetic strategy that achieves the in situ introduction of Zn sites and morphology modulation of the catalysts. The optimized ZnO@MFI-P catalyst yields a propylene formation rate of 57.9 mmol_propylene·g_cat^–1·h^–1 at 580 °C with a propylene selectivity over 95%, which is superior to bulk ZnO@MFI-B, as well as the state-of-the-art Zn-based PDH catalysts. The combined theoretical and experimental efforts evidence that the MFI-P with preferential exposure of straight channels benefits the regioselective distribution of Zn species within the straight channels. This contributes to the formation of isolated [ZnOH] species and the derived [ZnH] sites, therefore facilitating propane activation toward efficient PDH performance over the ZnO@MFI-P catalyst.