Synergistic COF/FeOF cascade catalysis enables efficient self-Fenton degradation of β-lactam antibiotics

Conventional Fenton processes are constrained by the inherent requirements of acidic pH and continuous exogenous H₂O₂ supply. Herein, we developed a COF/FeOF cascade system that integrates in-situ H₂O₂ generation with immediate activation, enabling an efficient self-Fenton system. Under visible light, this dual-catalyst system achieved wide-pH adaptability, with an amoxicillin (AMX) degradation rate constant 11.2 times higher than that of pristine COF. This enhancement was attributed to the rapid and cumulative generation of hydroxyl radicals (•OH, 18.07 μM within 30 min). Density functional theory (DFT) calculations revealed that the strong electronegativity of F in FeOF intensifies the Lewis acidity of Fe centers, creating a thermodynamic driving force for H₂O₂ capture. This electronic interaction not only facilitates directional H₂O₂ transfer from the COF surface but also weakens the OO bond, lowering the energetic barrier for •OH evolution. The system maintained robust AMX degradation over 7 h of continuous operation. Combined with reactive site predictions and LC-MS analysis, the β-lactam ring cleavage pathways were elucidated, and toxicity assessments confirmed effective detoxification. This study presents a dual-catalyst cascade that overcomes the pH and exogenous H₂O₂ addition bottlenecks of traditional Fenton chemistry, achieving sustainable degradation of refractory antibiotics.