Green Hydrothermal Synthesis of Dual‐Phase Submicron Cu 2 O‐CuO Particles Using Corn Husk Extract for Enhanced Antibacterial Applications

Abstract The development of sustainable antibacterial materials is critical for addressing waterborne pathogens and rising microbial resistance. This study reports a green hydrothermal synthesis of dual‐phase submicron Cu 2 O‐CuO particles using corn husk extract as a natural reducing and stabilizing agent. Structural characterization confirmed the formation of monoclinic CuO and cubic Cu 2 O, each contributing uniquely to antibacterial activity: CuO promotes reactive oxygen species (ROS) generation, while Cu 2 O facilitates membrane disruption. Synthesis parameters, including temperature and duration, were systematically optimized; the sample synthesized at 100 °C for 6 h (G–Cu100–6) exhibited the most favorable phase composition, smallest particle size (∼0.16 µm), and highest antibacterial efficacy. G–Cu100–6 produced inhibition zones of 13.8 ± 0.3 mm against Staphylococcus aureus and 13.5 ± 1.0 mm against Escherichia coli . Compared to synthesis conducted without plant extract, the green method yielded more uniform particles with superior antibacterial performance. The enhanced activity is attributed to the synergistic interaction between Cu 2 O and CuO phases. This scalable, environmentally benign synthesis approach not only valorizes agricultural waste but also provides a promising platform for developing next‐generation antimicrobial materials for potential use in coatings, textiles, and water purification systems.