Abstract:
The green synthesis of transition metal oxide nanocomposites using Litseaglutinosa leaf extract presents a environment friendly approach that eliminates the need for toxic chemicals, offering a promising solution to global issues such as non-biodegradable dye pollution and antibiotic resistance. In this study, binary (Co₃O₄/ZnO, ZnO/CuO, CuO/Co₃O₄) and ternary (CuO/ZnO/Co₃O₄) nanocomposites were synthesized via a green route and characterized using UV-Vis, FT-IR, XRD, and SEM-EDS techniques. The ternary CuO/ZnO/Co₃O₄ nanocomposite displayed a reduced band gap of 1.6-3.04 eV with dual absorption peaks at 271 nm and 523 nm, signifying enhanced visible light absorption. XRD confirmed the successful formation and crystalline nature of each composite, with crystallite sizes of 12.45 nm (ZnO/Co₃O₄), 8.93 nm (CuO/Co₃O₄), 26.53 nm (ZnO/CuO), and 21.61 nm (ZnO/CuO/Co₃O₄). SEM analysis revealed distinct morphologies, spherical-rod (ZnO/Co₃O₄), porous spongy (CuO/Co₃O₄), butterfly-like (ZnO/CuO), and irregular hybrid structures (ternary) while EDX confirmed the elemental purity and uniform distribution. Photocatalytic testing under direct sunlight (at 7 ppm dye, 0.6 mg catalyst, pH 11, and 180 min) demonstrated that CuO/ZnO/Co₃O₄ exhibited the highest MB degradation efficiency (95 %) and the fastest reaction rate (1.69×10⁻² min⁻¹), outperforming the binary composites. Antibacterial tests against E. coli showed moderate activity across all samples, with CuO/Co₃O₄ achieving the largest inhibition zones (8–16 mm). These findings indicate that the synthesized nanocomposites have potential for environmental remediation and antibacterial applications.
Keywords:LitseaGlutinosa; Methylene blue; Nanocomposites; Photocatalytic activity; Antimicrobial activity; Dye degradation.