Room-Temperature Depolymerization of Waste Polycarbonate and Polyester Enabled by an Electrochemically Generated Local Alkaline Microenvironment.

Abstract

Driven by massive production and inadequate end-of-life management, polycarbonate and polyester plastic pollution has become one of the most critical environmental crises. To address this mounting challenge, decades of research have yielded a variety of polycarbonate and polyester recycling technologies. Nevertheless, the majority of existing methods either afford low-quality, low-value products or depend on harsh conditions such as high temperature, high pressure, and corrosive bases or acids, severely restricting their scalability and economic feasibility for industrial-scale implementation. Herein, we present an efficient electrochemical approach for the room-temperature depolymerization of polycarbonate and polyester into value-added monomers and derivatives, enabled by a cathodically in situ generated alkaline interfacial microenvironment at neutral bulk pH. This approach shows broad substrate compatibility with commercial-grade and contaminated waste polycarbonate, polyester, and their blends, affording corresponding products in up to 99% yields, with its industrial potential demonstrated by a kilogram-scale depolymerization reaction. Significantly, it realizes the direct recovery of high-performance long carbon fibers from reinforced composites without fiber-damaging pulverization, creating a viable upcycling route. Mechanistic studies confirm that water electroreduction generates surface hydroxyl species that act as proton shuttles, driving methanol deprotonation to form depolymerization-active species and establishing the indispensable alkaline microenvironment.