Tailoring Acid Sites in CeO ₂ for One-Pot Synthesis of Aviation Fuel from Biomass-Derived Ketones via Aldol Condensation and Hydrogenation

Developing efficient solid acid catalysts for converting biomass-derived carbonyls into high-energy-density aviation fuels remains challenging due to insufficient activity and stability. This work systematically investigates the mechanistic roles of Lewis and Brønsted acid sites in CeO2-based catalysts during the aldol condensation of cyclopentanone, revealing that Brønsted acid sites dominate self-condensation pathways, while Lewis acid sites govern cross-dimerization reactions. To optimize the strength and stability of the acid catalyst, a ZrO2–CeO2 composite (Ce–Zr–O) was developed via controlled metal oxide doping (33 wt % ZrO2), which achieves enhanced acid site distribution and synergy. When Ce–Zr–O-33 was supported on biomass-derived porous carbon (PC), the resulting Ce–Zr–O-33/PC catalyst demonstrated exceptional recyclability, with the target product yield increasing by 4.28% over five consecutive cycles. Further integration of bimetallic Ni–Cu (10 wt %) synergistically balanced condensation and hydrogenation functions, boosting the selectivity of alkanes to 73.68%. The optimized Ni–Cu (10)/Ce–Zr–O-33/PC catalytic system exhibits a dual-regulation mechanism: ZrO2 doping modulates the acid site density and strength, while Ni–Cu nanoparticles promote selective hydrogenation and stabilize intermediates. This work provides a scalable solid acid catalyst design framework for industrial biomass-to-fuel conversion, bridging the gap between mechanistic understanding and practical application in sustainable aviation fuel synthesis.