Atmospheric, continuous degradation of poly(ethylene terephthalate) waste by ZnO

Catalytic hydrogenolysis is a promising strategy for upcycling waste poly(ethylene terephthalate) (PET) into terephthalic acid, but the continuous degradation of PET was hindered by the use of high-pressurized flammable H 2 and the low degradation efficiency due to the slow H 2 diffusion in PET melt. Herein, we report the tandem strategy of Zn(II)-σ-Lewis acid/addition/nucleophilic attack using ZnO that achieves the atmospheric, organic solvent-free and continuous degradation of waste PET into terephthalic acid (yield>97 %). By activating the carbonyl group of PET, ZnO promotes β -scission to form vinyl-terminated intermediate, which subsequently undergoes the in-situ addition with the generated OH − nucleophilic site and the bound H 2 O on Zn II . In atmospheric conditions, PET is continuously degraded at a rate of 2.5 kg h −1 in laboratory, which is four orders of magnitude higher than the state-of-the-art catalysts.