One‐pot Hydrogenolysis of Polyethylene Terephthalate (PET) to p–xylene over CuZn/Al₂O₃ Catalyst

Abstract

Chemical upcycling of plastic wastes into valuable chemicals is a promising strategy for resolving plastic pollution, but economically viable methods currently are still lacking. Here, we report one‐pot hydrogenolysis of PET plastic into p‐xylene with an excellent yield (99.8 %) over a robust non‐precious Cu‐based catalyst, CuZn/Al2O3, in the absence of alcohol solvents. The presence of Zn species promotes the dispersion of Cu0 and increases the ratio of Cu+/Cu0, whereas the synergistic effect of Cu0 and Cu+ leads to a superior performance in the conversion of PET. The combination of GC‐MS, 13C CP MAS NMR, 2D 1H‐13C CP HETCOR NMR spectroscopy and kinetic studies for the first time demonstrates 4‐methyl benzyl alcohol as an important reaction intermediate in the hydrogenolysis of PET. Mechanistic studies indicate that the conversion of PET mainly follows a hydrogenolysis process, involving the cleavage of ester bonds to alcohols and the C‐O bond cleavage of alcohols to alkanes. This work not only brings new insight for understanding the upgrading pathway of PET, but also provides a guidance for the design of high‐performance non‐precious catalysts for the chemical upcycling of plastic wastes.