Bimetallic Synergistic Catalysis Enabling Efficient Chemical Recycling of Commercial Polyesters.

Poly-(ethylene terephthalate) (PET) is a globally mass-produced polyester that is vital to many industries, but its accumulation poses serious environmental challenges, necessitating efficient chemical recycling. However, the efficiency of these recycling strategies is limited by their inadequate catalytic performance. Herein, we developed a highly effective mononuclear Zn catalyst that achieves PET glycolysis with an activity of 1800 gPET gcat -1 h-1. Mechanistic investigations revealed that this complex serves as a precatalyst and undergoes in situ dimerization to generate dinuclear Zn species as the true active species. Most importantly, polyester depolymerization proceeds via a bimetallic synergetic catalytic mechanism, wherein the two Zn centers within a unified framework synergistically activate the carbonyl substrate and alkoxide species, thereby significantly facilitating nucleophilic addition. This catalytic system exhibits broad applicability, achieving >95% depolymerization efficiency for various polyesters and postconsumer plastic blends.