Synergistic Cu–Fe interactions in CuO ‐Fe₃O₄ catalysts for high‐activity Fenton‐like degradation of oxytetracycline in water

BACKGROUND The synthesis, characterization and performance evaluation of bimetallic CuO‐Fe₃O₄ catalysts in heterogeneous Fenton‐like degradation of oxytetracycline (OTC) in water was attempted. Influences of different catalyst compositions on the reaction behaviors were specifically elucidated. RESULTS By varying the Cu/Fe molar ratio, CuO‐Fe₃O₄ (2/5) was identified as the most effective catalyst, achieving near complete OTC and COD removal within 60 min. Its superior activity resulted from an optimal CuFe balance that enhanced metal dispersion, interaction, and •OH radical generation. The catalyst exhibited high surface area, narrow pore distribution, and minimal Fe leaching (~0.28 mg L −1 ), maintaining stable performance over five reuse cycles with negligible structural degradation. Calcination at 400 °C further improved activity, offering the best balance of surface reactivity, adsorption, and stability, while under‐ or over‐calcination (350 °C or 600 °C) reduced efficiency due to particle agglomeration leading to limited •OH production. Reaction parameters such as catalyst dosage, H 2 O 2 concentration, pH, and OTC loading significantly affected degradation. Optimum conditions were pH 3.0, 0.5 g L −1 catalyst, and 60 mg L −1 H 2 O 2 . Higher OTC concentrations or excess catalyst reduced efficiency through saturation or radical scavenging. CONCLUSION The enhanced catalytic activity arose from synergistic CuFe interactions that promoted •OH generation rather than surface area alone. Owing to its high activity, stability, low metal leaching, and reusability, the CuO‐Fe₃O₄ (2/5) catalyst shows strong potential for large‐scale water treatment and degradation of organic pollutants under acidic conditions.