Enhancing Propane Aromatization Performance of Zn/H-ZSM-5 Zeolite Catalyst with Pt Promotion: Effect of the Third Metal Additive-Sn

In this study, an attempt was made to modify Zn/HZSM-5 aromatization catalyst by successively impregnating Sn and Pt. Among prepared catalysts, the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst exhibited excellent catalytic performances in both activation and aromatics selectivity. Multi-techniques including XRD, nitrogen physisorption, NH3-IR, TEM, HAADF-STEM/EDX and operando dual beam Fourier transform infrared (DB-FT-IR) spectroscopy were applied to study Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst to gain insight into its active sites and collaboration of them. It is concluded that, in the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst, the aromatization of propane was catalyzed by the cooperation between BrOnsted acid sites (bridging hydroxyls)-Lewis acid sites [zinc species and metallic alloy (SnPt nano clusters)]. Sn had crucial mediation effect which remarkably improved metal dispersion and finely tuned metal-metal interactions. Furthermore, the 3000-h fixed-bed propane aromatization stability test indicated that the Zn6.0Sn0.2Pt0.1/HZSM-5 catalyst also had very prominent anti-coking deactivation ability. [GRAPHICS] .