Synergistic OH ⁻ /H ₂ O Engineering and Dynamic Potential Modulation for Efficient Upcycling of PET Waste to Glycolic Acid Using H ₂ O as the Oxygen Source

The conversion of polyethylene terephthalate (PET)-derived ethylene glycol (EG) into value-added glycolic acid (GA) by electrocatalysis using H₂O as an oxygen source is a promising pathway for the sustainable valorization of plastic waste. However, the commonly used Pt and Pd catalysts suffer from undesirable activity and fast deactivation. Herein, we designed a AuPtPdRh medium-entropy aerogel (MEA) with multi-site synergies, coupled with dynamic potential modulation strategy, to achieve efficient GA synthesis. The AuPtPdRh MEA reduces the overall energy barrier through a potential relay-type catalytic mechanism across distinct active sites. The potential sweep-step hybrid electrolysis (PS-SHE) modulation strategy establishes a "progressive pre-enrichment-pulsed cleaning-regeneration" cycle, which enhances catalytic activity and stability. This system achieves 98% Faradaic efficiency (FE) for GA (FE_GA), as well as an GA production rate (PR_GA) of up to 8.82 mmol cm^-2 h^-1. Additionally, it can maintain stable operation for 500 h at an ampere-level current density (0.25 A cm^-2) in a membrane-free flow cell. The universality of this approach is further demonstrated for methanol, ethanol, and propanol electrooxidation, providing a versatile platform for biomass valorization.