Pt supported on Zn modified silicalite-1 zeolite as a catalyst for n-hexane aromatization

Platinum（Pt）supported on Zinc（Zn）modified silicalite-1（S-1）zeolite（denoted as Pt-Zn/S-1）was prepared by using a wetness-impregnation method and applied in the n-hexane aromatization reaction for the first time.Both Lewis and Br?nsted acid sites were detected in Pt-Zn/S-1 catalyst by means of FT-IR adsorption of NH3 experiment,which were identified as mostly weak and medium ones.Besides,Pt and Zn species showed strong interaction,as revealed by the TPR（Temperature-programmed reduction）and XPS（X-ray photoelectron spectroscopy）experiments.Pt-Zn/S-1 catalyst exhibited excellent aromatization function rather than isomerization and cracking side reactions in the conversion of n-hexane.Pulse experimental study showed that 75.6% of n-hexane conversion and 76.8% of benzene selectivity were obtained over Pt0.1-Zn6.0/S-1 catalyst at 550℃ and under atmospheric pressure.By spectroscopy tests and pulse experimental results,it was concluded that the n-hexane aromatization over Pt-Zn/S-1 catalyst follows a metal-acid bifunctional mechanism.Furthermore,with the assistance of Zn,the electron-deficient Pt species in Pt-Zn/S-1 showed good sulfur tolerance performance.