Sustainable Conversion of Microplastics to Methane with Ultrahigh Selectivity by a Biotic–Abiotic Hybrid Photocatalytic System

Abstract Efficient conversion of microplastics into fuels provides a promising strategy to alleviate environmental pollution and the energy crisis. However, the conventional processes are challenged by low product selectivity and potential secondary pollution. Herein, a biotic‐abiotic photocatalytic system is designed by assembling Methanosarcina barkeri ( M. b ) and carbon dot‐functionalized polymeric carbon nitrides (CDPCN), by which biodegradable microplastics—poly(lactic acid) after heat pretreatment can be converted into CH 4 for five successive 24‐day cycles with nearly 100 % CH 4 selectivity by the assistance of additional CO 2 . Mechanistic analyses showed that both photooxidation and photoreduction methanogenesis worked simultaneously via the fully utilizing photogenerated holes and electrons without chemical sacrificial quenchers. Further research validated the real‐world applicability of M. b ‐CDPCN for non‐biodegradable microplastic‐to‐CH 4 conversion, offering a new avenue for engineering the plastic reuse.