Enhanced Dehydrogenative Aromatization of Propane by Incorporating Fe and Pt into the Zn/HZSM‑5 Catalyst

In this study, an attempt was made to modify the Zn/HZSM-5 aromatization catalyst by successively impregnating Fe and Pt. Multitechniques including NH3 adsorption FT-IR, TEM, HAADF-STEM, XPS, and operando dual beam FT-IR spectroscopy of propane aromatization were employed to investigate the interactions among Zn, Fe, and Pt and the synergetic catalysis among the Brønsted acid sites, Lewis acid sites, and metallic sites of the ZnFePt/HZSM-5 catalyst. Results show that an optimized trimetallic Zn1.0Fe0.3Pt0.1/HZSM-5 catalyst has much lower dry gas production and significantly enhanced propane transformation activity and aromatization selectivity compared with the parent Zn/HZSM-5. The excellent performance of the trimetallic catalyst could be attributed to the high dispersion of metals, the formation of FePt bimetallic dehydrogenation active sites, and the promotion effect of FePt sites for the recombinational desorption of H atoms for the [ZnOZn]2+ sites. The fixed-bed reaction indicates that the trimetallic Zn1.0Fe0.3Pt0.1/HZSM-5 catalyst also has excellent durability which is desirable for practical use.