Design of a composite catalyst system for CO2-assisted light alkane dehydro-aromatization.

Benzene and Xylene are key building blocks for robust polymer materials. They are typically obtained as side products of the production of high-octane gasoline and of naphtha cracking for light olefins. Dehydro-aromatization of light alkanes provides an alternative on-purpose process to produce these aromatic building blocks. Yet, it suffers from low aromatic yields and fast catalyst deactivation by coke formation. The introduction of CO2 during light alkane dehydro-aromatization potentially increases the aromatic yield by consuming H2 via the reverse water-gas shift reaction, while at the same time enhancing the stability of the catalyst and converting harmful CO2. In recent work, we showed that CO2 indeed increases the propene yield during propane dehydrogenation over a GaOx/HZSM-5 catalyst, but that CO2 conversion over this catalyst is limited. In this project, we propose a composite catalyst system, combining optimized GaOx/H-ZSM-5 to maximize the aromatic yield, with a doped CexM1-xO2 function to catalyze CO2 conversion. To minimize coke formation, H-ZSM-5 nanosheet catalysts are proposed.