Sustainable recycling of polyester wastes using a coordinatively unsaturated Zn catalyst

Closed-loop recycling of polyester waste offers a promising route for addressing the environmental burden of plastic pollution and enabling resource circularity. However, current polyester plastic recycling methods face limitations in industrial scalability and environmental impact. Here, we report the development of a low-cost, earth-abundant, coordinatively unsaturated defect–zinc oxide (d–ZnO) catalyst for the efficient depolymerization of various polyester wastes, including polyethylene terephthalate, biodegradable polyesters, post-consumer polyesters, and mixed polyester waste. Mechanistic investigations reveal that defects structure in the catalyst enhance the activation of oxygen and water molecules, generating nucleophilic species that drive ester bond cleavage via carbonyl activation. The robustness and scalability of our strategy were further validated through large-scale closed-loop recycling of polyester waste plastics. Life cycle assessment (LCA) and techno-economic analysis (TEA) demonstrate the environmental sustainability and economic viability of this process across multiple metrics, including human health, ecosystem quality, resource consumption, and production cost. This work offers a broadly applicable, sustainable, and practical solution for management polyester plastic waste. Hydrolytic polyethylene terephthalate (PET) depolymerization typically employs harsh acid or alkali conditions. Here, the authors develop a high efficiency defect-zinc oxide nanosheet catalyst for the hydrolytic depolymerisation of PET to terephthalic acid in water under neutral conditions.