The synergistic effect of Fe–Cu–Co multi-metals in activating low-concentration H2O2 for enhanced oxytetracycline degradation: efficiency and mechanism

The development of efficient and cost-effective catalytic systems for antibiotic degradation remains a significant challenge in environmental remediation. Herein, a novel Co/CuFe 2 O 4 composite was synthesized via a sol–gel combustion method to construct a multi-metal synergistic photocatalytic-Fenton-like system for the degradation of oxytetracycline (OTC). Density functional theory (DFT) calculations indicate that the incorporation of Co leads to a more negative material formation energy, suggesting that Co/CuFe 2 O 4 has a more stable electronic structure. This optimized electronic structure enhances the redox cycle (Fe 3+ /Fe 2+ , Cu 2+ /Cu + , and Co 2+ /Co 3+ ), thereby improving the activation efficiency at low concentrations of H 2 O 2 (0.1–6 mmol/L). Under optimal conditions (pH 3, 35 °C, 4 mmol/L H 2 O 2 ), the 13% Co/CuFe 2 O 4 catalyst achieved complete OTC degradation within 60 min, with an 0.1 mmol/L H 2 O 2 utilization rate of 17.81% at neutral pH. Moreover, the catalyst exhibited excellent stability, retaining 87.5% degradation efficiency after five cycles. Radical quenching experiments confirmed that ·OH, h + , and ·O 2 − were the dominant reactive species, while the synergistic effect of multiple metal redox pairs facilitated efficient electron transfer and H 2 O 2 activation. This work provides a promising strategy for designing high-performance Fenton-like catalysts with broad pH adaptability and low oxidant consumption, offering significant potential for the treatment of antibiotic-contaminated wastewater. Graphical