A synergistic catalyst of Fe/ZSM-5 for robust aromatics production via methane dehydroaromatization

Methane dehydroaromatization (MDA) was a promising technology for the synthesis of high value-added aromatics through natural gas. Fe/ZSM-5 catalysts were widely used in MDA reaction. However, its catalytic mechanism remained ambiguous. In this work, a novel one-pot strategy was developed for the preparation of Fe/ZSM-5 catalysts, which can delicately control the iron species and acidic property of Fe/ZSM-5 catalysts. In-situ DRIFTS and DFT calculation demonstrated that MDA followed a bifunctional mechanism and the second C–H bond breaking process of CH 4 was the rate-determining step, where methane underwent coupling and dehydrogenation at the iron active sites to generate intermediate species (ethylene), and Brønsted acid sites played a key role in determining the selectivity of aromatics. Moreover, CO-pulse chemisorption revealed the quantitative synergistic effect between metal active sites and Brønsted acid sites. Catalysts with highly dispersed iron oxide and proper density of Brønsted acid sites exhibited the best catalytic performance. This study elucidated the catalytic roles of iron species and Brønsted acid sites in Fe/ZSM-5 catalysts in MDA and provided guidance for the future development of highly active MDA catalysts.