Electrochemical Upgrading Plastic to Organosulfurs Through Fe-N₃ Single Atom Catalyst Under Ambient Conditions

Cycling and electrochemical upgrading of plastics present a sustainable approach to transforming waste into high-value chemicals, yet the focus has predominantly been on carbohydrate production, leaving the potential of organosulfur compounds largely unexplored. In this study, we introduced an efficient electrochemical strategy to convert polyethylene terephthalate (PET)-derived ethylene glycol (EG) into organosulfur compounds with high yields. A specially designed iron single-atom catalyst (SAC) supported on nitrogen-doped hollow carbon spheres (NHCS), which feature high catalytic activity of the Fe-N₃ motifs, was employed, which facilitates the C─C bond cleavage during EG oxidation, and generates formaldehyde (CH₂O) species. These intermediates subsequently react with S-containing nucleophiles, that is, SO₃ ^2-, to form hydroxymethanesulfonate (HMS) via C─S bond formation. Our method achieves a remarkable faradaic efficiency of over 60% and an unprecedented production rate of 1800 µmol cm^-2 h^-1 for HMS. Additionally, we validate the use of PET as feedstock for C─S bond formation, achieving a considerable faradaic efficiency of over 25% and an unprecedented production rate of 900 µmol cm^-2 h^-1. Our approach promises to enhance sustainability and profitability in plastic value chain management and revolutionize the production of pharmaceuticals, textile chemicals, and agrochemicals.