Concurrent production of glycolate and H2 via paired electrolysis: Ethylene glycol oxidation and hydrogen evolution from polyethylene terephthalate hydrolysate

Selective ethylene glycol oxidation reaction (EGOR) to specific C2 species offers a promising approach to pair with cathodic hydrogen evolution reaction (HER) for electrochemical upcycling of waste polyethylene terephthalate (PET) plastic into high-value chemicals and H 2 . Efficient catalyst with tailored adsorptive interaction strength with intermediates is pivotal to fulfill such a scenario. Herein, a self-supported PdNi/NF electrode with deposition of PdNi hybrid onto nickel foam (NF) substrate was prepared by a gentle replacement reaction, which demonstrated high catalytic activity for EGOR toward glycolate with high faradaic efficiency (90 ± 2 %), decent yield (0.7 ± 0.01 mmol h −1  cm −2 ) and acceptable stability at a low applied potential of 0.8 V, which enabled electrosynthesis of glycolate via electrooxidation of PET hydrolysate. Meanwhile, a self-supported Cu, Co bimetallic phosphide onto NF substrate (CuCoP/NF) was prepared for HER catalysis, which featured a low overpotential of 117 mV at cathodic current density ( J ) of −100 mA cm −2 and decent durability. The further pairing of anodic EGOR and cathodic HER enabled electrolysis of PET hydrolysate to coproduce glycolate and H 2 at an energy-saving manner. This work provides a viable paradigm for coproduction of glycolate and H 2 from electrochemical upcycling of PET plastic, and presents essential instruction for reclamation of obsolete resource via sustainable and waste-to-treasure manner.