Advanced catalyst design and mechanistic insights in electrocatalytic upcycling of PET-derived ethylene glycol and coupled electrolysis systems

Abstract

Polyethylene terephthalate (PET) is a major contributor to plastic pollution and a compelling feedstock for circular chemical manufacturing. Electrocatalytic upcycling has recently emerged as a scalable route that couples mild PET depolymerization with electricity-driven reforming of PET-derived ethylene glycol (EG) into value-added C1 and C2 oxygenates, while enabling integration with advanced reactor architectures. This Review provides a mechanism-centered synthesis of electrochemical PET valorization, with emphasis on EG oxidation reaction (EGOR) pathways and catalyst design principles. We first summarize PET upgrading strategies and outline electrochemical fundamentals from pretreatment and monomer recovery to key performance metrics in flow cells and membrane-electrode assemblies. We then analyze the mechanistic landscape of EGOR, contrasting C-C cleavage routes to formate with pathway modulation toward glycolate and glycolic acid, and highlighting how potential, electrolyte composition, and interfacial structure govern intermediate evolution and selectivity. Building on these insights, we survey state-of-the-art noble and earthabundant catalysts, distilling unifying themes in operando reconstruction, heterointerface engineering, and defect or dopant regulation. Finally, we discuss coupled electrolysis platforms that pair EGOR with hydrogen evolution, CO 2 reduction, or nitrate reduction to co-produce fuels and chemicals at reduced cell voltages.Perspectives are provided on catalyst durability, rigorous quantification, mechanistic validation, product separation, and system-level design toward practical PET electro-upcycling.