PtSn/MFI catalysts for propane dehydrogenation prepared by an impregnation–calcination–washing method

A simple and scalable impregnation–calcination–washing (ICW) method has been proposed for synthesizing PtSn/MFI catalysts. This study primarily investigates the impact of zeolite acidity, the order of preparation steps, and the influence of tin, NaCl, and water washing on the characteristics of ICW propane dehydrogenation catalysts. To improve the dispersion of Pt and Sn, a zeolite characterized by high external surface acidity was used as a support. In addition, a significant quantity of NaCl was employed during the impregnation process. Washing the zeolite surface to remove excess NaCl releases active sites and redistributes Pt. This preparation procedure resulted in the formation of highly active and stable propane dehydrogenation catalysts. The most efficient PtSn/MFI ICW catalyst exhibited an initial propane conversion of 36%, propylene selectivity of 96%, and a deactivation constant of 0.009 h−1 at 570 °C, with a weight hourly space velocity of 28 h−1. [Display omitted] •PtSn/MFI catalysts were prepared by an impregnation–calcination–washing (ICW) method.•ICW PtSn/MFI propane dehydrogenation catalysts show high activity and stability.•Zeolite external surface acidity enhances Pt dispersion and catalyst stability.•Excess NaCl promotes Sn and Pt dispersion and efficiently suppresses zeolite acidity.•Washing off an excess NaCl increases Pt accessibility and catalyst stability.