Breaking the Activity-Stability Trade-Off via Synergistic Integration of Surface Hydroxyl Coverage and Dynamic Potential Control for High-Efficiency Electrocatalytic Upcycling of PET Waste to Glycolic Acid.

The electrocatalytic valorization of waste polyethylene terephthalate (PET)-derived ethylene glycol (EG) into glycolic acid (GA) represents a promising route for plastic upcycling. Palladium (Pd) catalysts are widely employed for the selective production of GA via the EG electrooxidation reaction (EGOR); however, they are typically constrained by an intrinsic activity-stability trade-off. Herein, we report a porous (PtPd)2SnGa intermetallic metallene (denoted as PI-(PtPd)2SnGa-ene) coupled with a pulsed electrocatalysis (PE) strategy to achieve efficient GA synthesis. The unique p-d orbital hybridization and high oxophilicity of PI-(PtPd)2SnGa-ene facilitate the desorption of the key *O═C─CH2OH intermediate and the adsorption of OH- species. Moreover, dynamic potential modulation effectively removes the accumulated PdOx passivation layer formed at high potentials. The as-prepared PI-(PtPd)2SnGa-ene catalyst achieves a Faradaic efficiency (FE) for GA production exceeding 90% over a broad potential window from 0.8 to 1.2 V. When integrated with the PE strategy in a membrane-free flow electrolyzer (MFE) system, the catalytic system operates stably for 100 h, successfully reconciling high activity with long-term stability. This study provides new insights into the efficient and stable electrocatalytic upcycling of PET waste into GA.