Stepwise Hydrodeoxygenation of Mixed Oxygenated Plastics Enables Sequential Production of Jet- and Gasoline-Range...

Efficiently valorizing mixed oxygenated aromatic plastic waste into high-value chemicals remains a major challenge in sustainable waste management. Hydrodeoxygenation (HDO) is a promising strategy, but conventional catalysts often lead to complex product mixtures due to undesired C-C bond cleavage and isomerization. Here, we report a stepwise HDO strategy over a Rh/Nb₂O₅ catalyst that enables the selective and sequential conversion of mixed oxygenated aromatic plastics into well-defined cycloalkane products. This process achieves remarkable 92.3% yields of 1,1'-(1-methylethylidene)biscyclohexane (a C₁₅ cycloalkane suitable as an additive for aviation and jet fuels) and 86.1% yields of C₆-C₈ cycloalkanes for gasoline, from mixed feedstocks including polycarbonate (PC), poly(phenylene oxide) (PPO), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Mechanistic investigations reveal that the catalyst's abundant Lewis acid sites, minimal Brønsted acidity, and strong affinity for aromatic and oxygenated groups synergistically enable sequential C═C hydrogenation and selective C-O bond hydrogenolysis, while effectively suppressing C-C bond cleavage. The system exhibits excellent tolerance to contaminants in real-world plastic wastes, supporting its practical applicability. Techno-economic and life cycle assessments further confirm the environmental and economic viability of the process. This work provides a general strategy for precision upcycling of complex plastic mixtures into fuel-range cycloalkanes and offers design principles for catalytic control of oxygenated polymer valorization toward circular plastic economies.