Propane Aromatization Tuned by Tailoring Cr Modified Ga/ZSM-5 Catalysts

Accelerating propane dehydrogenation in propane aromatization is vital because it is the first and rate control step. In this study, we introduced Cr to Ga/ZSM-5 by tuning its impregnation sequence and amount, which was expected to accelerate the dehydrogenation step and improve aromatization performance. The impregnation sequence of Cr on catalyst not only affected the interaction between Ga and ZSM-5, but also tuned the amount of dehydrogenation active species Cr³⁺. Due to the plenty of Cr³⁺ species and strong interaction between Ga species and ZSM-5, 2Cr/GaZ5 catalyst accelerated the dehydrogenation step and improved the aromatization process. More light hydrocarbons were preferred to be produced and were further converted into BTX on 2Cr/GaZ5 catalyst. Excessive Cr on catalyst caused the formation of Cr₂O₃ particles with worse dispersion. The aggregated Cr₂O₃ decreased the strong acidity of catalyst, which could not further promote propane conversion and decreased the aromatization ability of catalyst.