Modulated oxidation pathways enabled by CoFe bimetallic alloy catalysts for effective elimination of antibiotics

The persistent distribution of antibiotics and antibiotic resistance genes (ARGs) in wastewater poses a critical threat to environmental security and public health. Herein, a bimetallic cobalt‑iron (CoFe) alloy catalyst supported on nitrogen-doped carbon (PBA@C-X, where X denotes the melamine-to-Co-Fe Prussian blue analogue (PBA) ratio) was constructed via pyrolysis of precursors. Synergistic CoFe alloy sites effectively modulate electronic structure, enabling selective reactive oxygen species (ROS) generation that promotes targeted degradation of tetracycline hydrochloride (k = 0.58 min^-1) and in situ attenuation of ARGs. Notably, a transition in the dominant ROS from superoxide radicals (•O₂^-) to singlet oxygen (¹O₂) was confirmed through electron paramagnetic resonance (EPR) spectroscopy and steady-state ROS quantification from PBA@C-0 to PBA@C-3. Kinetic correlation and density functional theory (DFT) calculations confirmed the CoFe alloy sites as the principal active centers, facilitating elevated electron transfer quantity from the nitrogen-doped carbon matrix to peroxymonosulfate (PMS). Moreover, the PBA@C-X catalyst demonstrated effective degradation of tet resistance gene. Fukui function analyses of guanine derivatives further identified potential oxidative attack sites within the ARG backbones and nucleobases, elucidating their efficient in situ conversion into inactive small molecules. Continuous-flow experiments further confirmed the excellent long-term operational stability and reusability. This study provides a comprehensive mechanistic understanding of ROS modulation through electronic structure engineering in Co-Fe-based catalysts and proposes a flexible, tunable strategy for advanced oxidation processes (AOPs), imparting key mechanistic insights that facilitate the systematic design of catalysts for extracellular ARG abatement.