Boosting in-situ Fenton-like degradation on bifunctional CoFe-CoFe2O4@N-C via constructing “adsorption trap”: Unveiling the role of pyrrolic N

The rational design and construction of bifunctional catalysts with excellent adsorption and catalytic activity are meaningful but challenging. Herein, a core–shell magnetic CoFe-CoFe2O4@N-C catalyst with dual sites was constructed to shorten the migration distance between the target contaminant of ofloxacin (OFX), a typical antibiotic, and reactive oxygen species (ROS) in Fenton-like degradation. The characterization results and theory calculations indicated that abundant pyrrolic N sites on shells served as “adsorption traps” for OFX and encapsulated CoFe2O4 as activation sites for peroxymonosulfate (PMS). The unique reaction pathway between in-situ generated ROS and adjacent adsorbed OFX enhanced the catalytic ability, showing 100% removal of OFX (20 mg/L) with a high rate constant (0.422 min−1). Meanwhile, the system presented excellent anti-interference capability to inorganic (Cl–, NO3–, and H2PO4–), organic (humic acid), actual aqueous matrices (tap water and river water), and good stability proved by the continuous flow experiment. The work will provide ideas for designing bifunctional catalysts and supply an eco-friendly process for boosting in-situ Fenton-like degradation.