• • The Fe3O4@UiO/IKCN catalyst achieves efficient phenol degradation without external H2O2 or Fe2+ addition, operating at circumneutral pH (pH ~7) and producing negligible iron sludge, overcoming key limitations of conventional Fenton processes.
• • Under visible light, the catalyst selectively reduces dissolved O2 to H2O2 via a two-electron transfer pathway, with in-situ H2O2 generation rates sufficient to sustain Fenton reactions, as confirmed by cumulative concentration measurements.
• • The Fe3O4 nanoparticles provide active sites for H2O2 activation and facilitate Fe(III)/Fe(II) cycling, enhancing electron-hole separation and enabling sustained generation of hydroxyl radicals (·OH) for pollutant mineralization.
• • The catalyst exhibits a wide pH applicability range (tested from acidic to circumneutral), maintaining high degradation efficiency, which is critical for treating real industrial wastewater with variable pH.