Green synthesised ZnO/CuO nanocomposites for energy storage, environmental remediation and optoelectronic applications

Zinc oxide/Copper oxide (ZnO/CuO) nanocomposites (NCs) have gained substantial importance due to their synergistic structural, electrical, optical and photocatalytic properties. In this study, ZnO/CuO NCs were synthesized using a green solution combustion method with lemon extract as fuel. X-ray diffraction (XRD) confirmed the formation of highly crystalline ZnO and CuO phases, while scanning electron microscopy (SEM) revealed an agglomerated morphology. UV–visible (UV–Vis) spectroscopy indicated an optical bandgap of 3.27 eV and photoluminescence (PL) analysis demonstrated strong near-band-edge and defect-related emissions. Dielectric studies highlighted superior charge storage capabilities, making these materials promising for energy storage applications. Photocatalytic investigation on crystal violet dye degradation under visible light showed an 83% efficiency at neutral pH, emphasizing their environmental remediation potential. The ZnO/CuO heterostructure facilitates enhanced charge separation and light absorption, boosting performance in opto-electronic devices. This study provides a comprehensive evaluation of ZnO/CuO NCs, positioning them as multifunctional materials for sustainable energy, environmental and technological applications.