Long-Chain Branched α-Alkenes from Plastic Upcycling Using Mo 2 C–Zn Nanoclusters Embedded on Hierarchical Porous Carbon

The use of plastics has led to widespread waste and severe environmental impacts. Herein, a decomposition–catalysis upcycling strategy using M–Zn codoped hierarchical porous carbon (M–Zn/HPC) was proposed for polypropylene (PP) upcycling into highly valuable long-chain branched α-alkenes. Zn/HPC-II, synthesized via a two-step carbothermal reduction, exhibited excellent catalytic activity for the conversion of PP to C4–C18 liquid hydrocarbons. Furthermore, bimetallic Mo 2 C–Zn/HPC exhibited the best catalytic performance, achieving a liquid yield of 887.3 mL/kg PP and 54.5 Cmol % selectivity for long-chain branched α-alkenes. The catalytic mechanism involves thermal degradation of PP via free radical scission, followed by reforming on Mo 2 C–Zn/HPC, where Mo 2 C with lattice distortions facilitated C–H bond activation and synergized with Zn/HPC acid sites to β-scission and related reactions, efficiently producing long-chain branched α-alkenes. The robust stability of Mo 2 C–Zn/HPC was further confirmed using real-life PP plastic wastes. Overall, this study presents a promising strategy for converting PP waste into high-value long-chain branched α-alkenes.