Boosting CO2-to-Aviation Fuel Fraction over an Inverse Structured KFeZr Tandem Catalyst

Abstract CO2 hydrogenation to aviation fuel-range hydrocarbons (C8–C16) offers a route to lowering net carbon emissions in the aviation sector, but achieving high selectivity to this fraction remains challenging. Herein, we report a synergistic strategy integrating an inverse-structured KFeZr catalyst with a CO-mediated “hydrogen pump” mechanism over HZSM-5. The inverse architecture, characterized by highly dispersed ZrO2 nanodomains anchored on Fe phases, induces strong metal interactions that stabilize an optimal phase composition (Fe5C2/Fe3O4 ≈ 1.2). This configuration not only provides physical passivation of over-active chain-growth sites but also yields enriched oxygen vacancies and an approximately 3.2-fold increase in interfacial site density compared to conventional counterparts. Upon coupling with HZSM-5, the tandem system delivers a 22% increase in selectivity for the aviation fuel-range fraction. Mechanistic studies identify CO as a “hydrogen pump” that regulates hydrogen transfer within the zeolite, thereby promoting dehydrocyclization and aromatization; introducing CO into the feed further raises this selectivity to 39.7%. This work provides critical insights into interfacial design and intermediate-mediated hydrogen regulation for high-performance liquid fuel synthesis.