Redox Synergism in Cu–Co Bimetallic Oxides for Superior Advanced Oxidation of Industrial Dyes

Abstract The need for effective and reusable catalysts for advanced oxidation processes (AOPs) stems from the growing contamination of water bodies by persistent organic dyes like methylene blue (MB). In this work, we present the simple hydrothermal synthesis of CuO/CuO–Co 3 O 4 nanostructures (NSs) and their use as heterogeneous catalysts for the oxidative degradation of MB in an aqueous environment. Several analytical methods verified the formation of the nanostructure, production of hydroxyl radical (•OH), and the presence of strong Co–Cu interfacial interactions. The initial organic load of MB was taken in the range of 5–15 mg/L. and the nanostructure achieved > 99% degradation within 60 min at 65 °C and retained > 91% efficiency after four cycles, demonstrating remarkable stability. The degradation mechanism was controlled by pseudo‐first‐order kinetics, with activity increasing with temperature, catalyst loading, and H 2 O 2 concentration but decreasing at higher dye concentration. This study presents a reusable, affordable material for environmentally friendly wastewater treatment while highlighting the synergistic Co–Cu impact in enhancing oxidative catalysis.