Tandem hydropyrolysis–hydrogenolysis of polyolefin wastes over morphology‐tuned <scp> Co ₃ O ₄ </scp> for jet‐fuel hydrocarbons

Abstract Polyolefin waste hydrogenolysis is constrained by high H 2 pressure, heat–mass transfer limitations, and broad product distributions. Here, a tandem hydropyrolysis–hydrogenolysis strategy decouples polymer depolymerization from hydrogenation, enabling selective low‐pressure upgrading of polyethylene (PE) and polypropylene (PP) to jet fuel‐range hydrocarbons (C 8 –C 16 ). Morphology‐tuned Co 3 O 4 catalysts form Co@CoO core–shell structures enriched with oxygen vacancies, facilitating H 2 dissociation and selective C–C cleavage. Under optimized conditions (540°C, 200°C, catalyst‐to‐feedstock mass ratio ( C / F ) of 4, 1.8 bar H 2 ), an 82.6% liquid yield with 83.7% jet‐fuel selectivity was achieved using standard PE powders, while real medical plastics gave 75%–78% yields. PE mainly produced linear alkanes, whereas PP yielded branched products, enabling fuel tuning. Density functional theory calculations show that oxygen vacancies lower the H 2 dissociation barrier and promote non‐terminal C–C bond activation in n ‐butane. This tandem route offers a scalable, non‐noble pathway to jet fuel from polyolefin waste.