Electrocatalytic\nOxygen Self-Sufficiency System Enables\nSinglet Oxygen Production for Water Decontamination

Electrochemical advanced oxidation process represents\na promising\nstrategy for water decontamination, but the parasitic anodic side\noxygen evolution reaction always causes a low energy utilization efficiency.\nIn this study, we address this limitation of developing an electrocatalytic\noxygen self-sufficiency system. This system established an integrated\nelectrocatalytic process that ran solely on O<sub>2</sub> produced\nby anodic oxygen evolution, followed by transformation of O<sub>2</sub> into H<sub>2</sub>O<sub>2</sub> at the nanoconfined Fe<sub>2</sub>O<sub>3</sub> cathode, which then led to the generation of <sup>1</sup>O<sub>2</sub>. The performance of water decontamination was evaluated\nusing tetracycline (TC), bisphenol A (BPA), and perfluorooctanoic\nacid (PFOA) as model emerging contaminants. When anodic polarization\nwas applied at 2.0 V vs the standard hydrogen electrode, the removal\nof TC, BPA, and PFOA with a flow rate of 10 mL min<sup>–1</sup> could reach 90.1%, 92.1%, and 62.2%, respectively. Electron spin\nresonance and radical quenching results indicated <sup>1</sup>O<sub>2</sub> as the main reactive oxygen species for TC and BPA decomposition,\nwhereas PFOA decomposition was contributed by direct electron transfer.\nThe intermediate toxicity was predicted to be reduced, and the excellent\nanti-interference ability of this system was proved in actual water.\nThese findings suggest a reagent-free and oxygen-dependent sustainable\nsystem for water decontamination.