From Plastic Waste to Value-Added Chemicals: A Trimetallic MOF Strategy for Electrochemical PET Upcycling

Abstract

Electrocatalytic upcycling of polyethylene terephthalate (PET) plastics into valueadded chemicals provides a sustainable route to simultaneously mitigate plastic pollution and enable energy-efficient chemical synthesis. Herein, we develop a tri-metallic NiMnCo metalorganic framework (NiMnCo-MOF) as a highly efficient electrocatalyst for advanced oxidation of PET-derived ethylene glycol (EG). As compared to pristine Co-MOF, the incorporation of Ni and Mn induces a pronounced morphological evolution, yielding ultrathin, loosely interwoven nanosheet architectures with abundant exposed edges and hierarchical porosity. Additionally, the modulated electronic structure of the metal centers facilitates the significant reduction in charge-transfer resistance and increases the electrochemically active surface area, thereby accelerating reaction kinetics. Consequently, the NiMnCo-MOF offers a Faradaic efficiency of 98% for selective EG-to-formate conversion, demonstrating excellent activity and selectivity under alkaline conditions. Importantly, terephthalate (TPA) recovered from PET hydrolysate is successfully reused as a linker to synthesize Co-MOF, which exhibits electrochemical performance comparable to that of Co-MOF derived from commercial TPA, highlighting the intrinsic recyclability of the catalyst-plastic system. These findings advocate a closed-loop strategy integrating plastic waste valorization, multimetal MOF engineering, and efficient electrochemical conversion, offering fundamental insights for the rational design of advanced catalysts toward sustainable energy and environmental applications.