ZnO/Fe₃O₄/CuO nanocomposites: surface plasmon resonance and charge separation for enhanced photocatalytic methylene blue degradation

This study investigates the optical properties and photocatalytic performance of ZnO, Fe₃O₄, and CuO nanoparticles (NPs), as well as their nanocomposites, synthesized via pulsed laser ablation in liquids (PLAL). Comprehensive characterization using UV–visible absorption spectroscopy, X-ray diffraction, and scanning electron microscopy revealed that the nanocomposites exhibit enhanced and broadened light absorption due to synergistic interactions and surface plasmon resonance (SPR) effects. The photocatalytic activities of these materials were evaluated through the degradation of methylene blue (MB) dye under visible light irradiation. Results demonstrated that the nanocomposites, particularly those combining CuO and ZnO, achieved superior degradation efficiencies compared to individual NPs, attributed to improved charge separation, defect-mediated activity, and plasmonic enhancement. These findings highlight the potential of engineered nanocomposites for efficient and reusable photocatalytic wastewater treatment.