CO2-assisted ethane aromatization over zinc and phosphorous modified ZSM-5 catalysts

The tandem reactions of CO2-assisted oxidative dehydrogenation and aromatization (CO2-ODA) of ethane were investigated over ZSM-5 modified with zinc (Zn) and phosphorus (P) by experimental studies and DFT calculations. The nature of active Zn species and their interaction with P were elucidated for understanding Zn/P-ZSM-5 catalyzed CO2-ODA reaction of ethane. Compared to the direct dehydrogenation and aromatization (DDA) reaction, the Zn/P-ZSM-5 catalyst possessed higher ethane conversion, enhanced aromatics yield, and better stability in the CO2-ODA reaction. The presence of CO2 reduced the carbon deposition, stabilized the Zn species, and thereby facilitated the generation of more liquid aromatics in CO2-assisted ethane aromatization. In situ characterization and DFT calculations provided insight into the mechanisms of CO2-ODA over the Zn/P-ZSM-5 catalyst.