FeIII-Driven Self-Cycled Fenton via Contact-Electro-Catalysis for Water Purification

While Self-cycled Fenton (SC-Fenton) systems represent an innovative advancement in water purification technologies, their practical implementation remains constrained by inefficient in-situ H2O2 generation. To address this limitation, we developed a mechano-driven contact-electro-catalysis (CEC) platform employing fluorinated ethylene propylene (FEP) as a triboelectric catalyst. Under ultrasound irradiation, this system achieves an exceptional H2O2 generation rate of 7.67 mmol·gcat–1·h–1, outperforming conventional piezo-catalysis systems. Mechanistic studies reveal that a built interfacial electric field generated on FEP surface effectively reduces the free energy for the indirect 2e– water oxidation pathway. This unique characteristic promotes the generation of interfacial hydroxyl radical (*OH) and enhances its subsequent recombination into H2O2. The strategic integration of FeIII as a catalytic initiator with the CEC system enables the establishment of SC-Fenton reaction (FeIII/FEP/CEC). Notably, the contact-electrification electrons accumulated on the FEP interface drive efficient FeIII/FeII redox cycling, achieving a remarkable degradation rate for sulfadiazine at 0.125 min–1. This enhanced catalytic performance stems from FeIII-mediated amplification of dissociative hydroxyl radical (•OH) generation. This study provides fundamental insights into the underlying mechanisms of CEC mediated FeIII-initiated SC-Fenton reaction, offering new possibilities for sustainable water purification processes.