Cascade degradation and electrocatalytic upcycling of waste poly(ethylene terephthalate) to valued products

The global annual production of poly(ethylene terephthalate) (PET) has reached 82 million tons, yet only a small fraction (less than 20%) is recycled. The ultra-slow degradation rate of PET results in the accumulation of PET waste in the environment, causing serious plastic pollution and posing severe challenges to ecosystems. In response, great efforts have been directed toward developing a cascade degradation and electrocatalytic upcycling strategy, which serves as a “waste-to-wealth” pathway. This strategy involves electro-reforming PET-hydrolyzed intermediates or using PET pyrolyzed products as electrocatalysts to generate high-value products. This review provides an overview of the state-of-the-art strategies for the “degradation-electrocatalytic upcycling (De-eUp)” of PET waste. Initially, an introduction to the strategy is provided, categorizing it into two main frameworks: “pyrolysis-electrocatalytic upcycling” and “hydrolysis-electrocatalytic upcycling”. The section on “pyrolysis-electrocatalytic upcycling” delves into the degradation methods for designing derived carbon nanomaterials and their utilization as high-performance electrocatalysts. The “hydrolysis-electrocatalytic upcycling” section discusses recent advancements in electro-reforming of PET hydrolyzed intermediates for the production of C₁ and C₂ products. The review concludes by examining the challenges and future prospects in developing an efficient and economical PET upcycling strategy. It is anticipated that this review will stimulate further progress in plastic waste valorization.