Revealing Electronic Effect in Mesoporous Medium-Entropy Alloy for Promoting Electrocatalytic Upcycling of Polyethylene Terephthalate Plastic

The electrochemical valorization of polyethylene terephthalate (PET) plastic waste into high-value C 2 products represents an attractive route for waste resource reutilization, and it is critical to identify advanced catalysts for PET-derived ethylene glycol oxidation reaction (EGOR) with high activity and selectivity. Herein, a mesoporous PtPdRuOs medium-entropy alloy (MEA) film on Ni foam (MEA-mPtPdRuOs/NF) is reported for electrosynthesis of glycolic acid (GA) from PET-derived ethylene glycol (EG), accompanying with cogeneration of hydrogen. MEA-mPtPdRuOs/NF demonstrates optimized Faradaic efficiency (95.2%) for GA production in PET hydrolysate. Experimental and theoretical analyses reveal a synergistic catalytic effect of the MEA in highly efficient EG-to-GA conversion, in which the Pt/Pd sites are responsible for the activation of EGOR intermediates and Os/Ru sites are contributed to water dissociation and *OH adsorption. Furthermore, the optimized electronic effect can reduce the EGOR energy barrier and enhance the C–C bond energy in key *OC–CH 2 OH intermediates, resulting in a higher performance for EG-to-GA conversion. In addition, the easy removal of poisonous CO species and high corrosion resistance make MEA-mPtPdRuOs/NF more stable for EGOR. This study proposes the rational design of a mesoporous MEA for the coproduction of valuable GA and H 2 via waste PET electroupcycling.