In the present work, a 0.5 at% CuO–CdS nanocomposite was successfully synthesized using a facile chemical method and systematically investigated for its structural, morphological, optical, and photocatalytic properties. X-ray diffraction (XRD) analysis confirmed the coexistence of hexagonal CdS and monoclinic CuO phases without the formation of secondary impurities, indicating successful heterostructure formation. Field emission scanning electron microscopy (FESEM) revealed significant morphological modification in the composite, exhibiting hierarchical flower-like and rod-shaped nanostructures with enhanced surface roughness. Energy dispersive X-ray (EDX) analysis verified the presence of Cu, Cd, S, and O elements, confirming phase purity, while FT-IR spectroscopy confirmed the formation of characteristic Cu–O and Cd–S bonds along with surface hydroxyl groups. UV–visible absorption studies demonstrated enhanced visible-light absorption and a slight red shift in the CuO–CdS nanocomposite compared to pure CdS, indicating improved light harvesting ability. Photoluminescence (PL) analysis showed significant quenching of emission intensity in the composite, suggesting efficient suppression of electron–hole recombination due to effective charge separation at the CuO/CdS interface. The photocatalytic activity of the synthesized nanocomposite was evaluated through the degradation of methylene blue (MB) dye under UV–Visible irradiation. The CuO–CdS heterostructure exhibited superior degradation efficiency compared to individual components, attributed to enhanced charge transfer and the generation of reactive oxygen species. The results demonstrate that the CuO–CdS nanocomposite is a promising material for visible-light-driven photocatalytic applications and wastewater treatment.

Keywords: Nanocomposite; CuO-CdS; Chemical Precipitation Method;