A polyphenol-engineered interfacial framework enables aeration-free electro-Fenton via localized oxygen enrichment

The practical application of the electro-Fenton (EF) process for antibiotic degradation is severely hampered by the sluggish mass transfer of dissolved oxygen, fundamentally coupling its performance to inefficient bulk aeration. Here, we overcome this limitation by proposing a “Localized Oxygen Enrichment Framework” (LOEF) strategy. This framework is constructed via the molecular self-assembly of a plant-derived polyphenol (tannic acid, TA) on the cathode, creating a synergistic interface that combines chemical O₂ anchoring with physical confinement to form a self-sufficient, oxygen-rich microenvironment. This engineered architecture endows the TA-modified electrode (TPC) with a substantially enhanced O₂ affinity and facilitates highly selective 2e⁻ ORR, enabling efficient in situ H₂O₂ generation. Experimentally, the TPC electrode achieves a high H₂O₂ yield of 25.5 mg L⁻¹, an oxygen utilization efficiency (OUE) of 33.88% under aeration-free conditions. Importantly, the TPC electrode maintains stable H₂O₂ production and faradaic efficiency over repeated operational cycles, demonstrating excellent electrochemical durability. The localized oxygen enrichment also supports rapid pollutant oxidation, allowing complete degradation of sulfathiazole within 120 min, with a rate constant 2.9-fold higher than its unmodified counterpart. Structural and spectroscopic analyses, along with DFT calculations, further confirmed the formation of TA-induced redox active interface regions, which accelerated the generation of reactive oxygen species (ROS). These findings offer a promising pathway toward the development of high-efficiency, sustainable electrochemical water treatment technologies.