Depolymerization of polyesters by a binuclear catalyst

Remediation and reuse of discarded plastics can reduce their accumulation in the environment and bring energy savings for plastic production. Here we discover a binuclear zinc catalyst that features a biomimetic intramolecular pathway for polyester depolymerization, which not merely enables environmental degradation of PET but also affords industrial-scale PET recycling under relatively mild conditions. The binuclear catalyst delivers a specific activity of 36 mg_PET d^-1 g_catal^-1 toward PET depolymerization at pH 8 and 40 ^oC, the very condition holding the possibility of naturally breaking down plastic waste. The structural stability of this synthetic catalyst allows it to work under wide operational conditions, resulting in a specific activity of 577 g_PET h^-1 g_catal^-1 at pH 13 and 90 ^oC for centralized PET recycling. A closed-loop production of bottle-grade PET was also demonstrated. Besides, this catalyst is catalytically active toward a wide scope of substrates with high tolerance to additives and impurities.