Quantitative Electrocatalytic Upcycling of Polyethylene Terephthalate Plastic and Its Oligomer with a Cobalt-Based One-Dimensional Coordination Polymer Having Open Metal Sites along with Coproduction of Hydrogen

Polyethylene terephthalate (PET) is the most used polymer, but its natural degradation kinetics is sluggish; therefore, its disposal poses an environmental threat. Here, we demonstrate electrocatalytic PET upcycling with full recyclability with a cobalt containing one-dimensional (1D) coordination polymer as an electrocatalyst that can operate at a low onset potential of 1.27 V vs. RHE, affording terephthalic acid (TPA) in 100% yield and potassium diformate (KDF) with ∼80% selectivity as isolated products, along with the coproduction of hydrogen. The mechanistic analysis, as obtained from systematic studies with PET, its oligomer, and monomer revealed a pathway for a side reaction generating carbonate (CO₃^2-) that follows a formate oxidation instead of an oxalate oxidation pathway. The catalytic performance and the mechanistic insight gained from the study, are useful in developing the PET upcycling technologies with maximized formate/KDF production.