Effect of Morphological Structure of PtSnNa/ZSM-5 on Its Catalytic Performance in Propane Dehydrogenation

The ZSM-5 zeolite with lfower-shaped crystallites (marked as ZFS) was synthesized through the hydrothermal preparation method. The properties of ZFS as a supporting material have been investigated in comparison with the traditional ZSM-5 zeolite. The prepared samples were characterized by XRD, N2 adsorption-desorption, TEM, NH3-TPD, XRF, and XPS techniques. The results showed that the formation of the lfower-shaped crystallites directly inlfuenced the physicochemical properties of ZFS material. In ZFS, the pore structure was changed, the acid content was decreased, and the surface properties were promoted. Besides, in the PtSnNa/ZFS catalyst, the amount of oxidized Sn species was remarkably increased and the dispersion of Pt was relatively improved. Meanwhile, due to these modiifcations, the capacity of the catalyst supported on ZFS to accommodate coke was greatly improved and the coke deposits on PtSnNa/ZFS were migrated from active metals to the support. Furthermore, as expected, the catalytic performance of the PtSnNa/ZFS catalyst for propane dehydrogenation to propylene and the stability of catalyst were signiifcantly improved.