Electrochemical Recycling of Poly(ethylene terephthalate): Controlling Ni/Cu Electrode Oxide Layers through Laser Treatment

Laser-assisted engineering of bimetallic electrocatalysts presents a promising strategy for tuning surface composition and reaction selectivity in alkaline oxidation processes. Herein, we investigate Ni/Cu alloy foil electrodes subjected to varying laser treatment intensities (0–100%) for the electrochemical oxidation of ethylene glycol (EG) to formate in 1.0 M KOH. The electrode treated at 50% laser power (Ni/CuL=50%) exhibited the highest formate Faradaic efficiency of 84.9% at 0.55 VHg/HgO, attributed to optimized surface NiOx phases and enhanced electrochemical surface area. Systematic spectroscopic analyses revealed laser-induced formation of Ni-rich surface layers, which underwent dynamic structural evolution under electrochemical conditions. Electrochemical impedance spectroscopy and Tafel analysis confirmed that laser treatment reduced charge transfer resistance and improved reaction kinetics. The system also demonstrated selective oxidation of hydrolyzed poly(ethylene terephthalate) and terephthalic acid derivatives, highlighting the relevance of this platform for waste-to-chemical conversion. This study demonstrates that pulsed or continuous-wave laser processing enables interfacial modulation of Ni/Cu catalysts, providing a tunable and scalable approach for selective EG oxidation and potentially other small-molecule transformations.