Salting-out effect enables highly selective electrosynthesis of oxalate from plastic waste.

Electrochemical upgrading of polyethylene terephthalate (PET)-derived ethylene glycol (EG) into value-added products offers a sustainable route toward a circular economy. However, achieving selective oxidation of EG to oxalate (OA) remains a challenge. Here, we propose an electrolyte engineering strategy that leverages the salting-out effect to achieve a maximum OA selectivity of 86%. By leveraging the low aqueous solubility of Na2C2O4, a Na+-containing alkaline electrolyte triggers the spontaneous precipitation of generated OA, sequestering it from the electrode to avert over-oxidation. This work opens a new paradigm for sustainable and economically viable PET recycling.