Electrocatalytic Oxygen Self-Sufficiency System Enables Singlet Oxygen Production for Water Decontamination

Electrochemical advanced oxidation process represents a promising strategy for water decontamination, but the parasitic anodic side oxygen evolution reaction always causes a low energy utilization efficiency. In this study, we address this limitation of developing an electrocatalytic oxygen self-sufficiency system. This system established an integrated electrocatalytic process that ran solely on O2 produced by anodic oxygen evolution, followed by transformation of O2 into H2O2 at the nanoconfined Fe2O3 cathode, which then led to the generation of 1O2. The performance of water decontamination was evaluated using tetracycline (TC), bisphenol A (BPA), and perfluorooctanoic acid (PFOA) as model emerging contaminants. When anodic polarization was applied at 2.0 V vs the standard hydrogen electrode, the removal of TC, BPA, and PFOA with a flow rate of 10 mL min–1 could reach 90.1%, 92.1%, and 62.2%, respectively. Electron spin resonance and radical quenching results indicated 1O2 as the main reactive oxygen species for TC and BPA decomposition, whereas PFOA decomposition was contributed by direct electron transfer. The intermediate toxicity was predicted to be reduced, and the excellent anti-interference ability of this system was proved in actual water. These findings suggest a reagent-free and oxygen-dependent sustainable system for water decontamination.