Plasmon-Enhanced Visible Light Photocatalysis Using CuO/Ag/ZnO/Mn2O3 Nanocomposites for Efficient Organic Pollutant Degradation

This study presents the development and evaluation of plasmonic CuO/Ag/ZnO/Mn2O3 nanocomposites tailored for enhanced photocatalytic degradation of methylene blue under visible light irradiation. Focused on optimizing the photocatalytic properties through the synergistic effects of metal oxides, the research involved the strategic incorporation of Ag, ZnO, and Mn2O3 into a CuO matrix. The inclusion of silver nanoparticles not only improved the charge carrier dynamics but also introduced localized surface plasmon resonance (LSPR) effects, significantly enhancing the absorption of visible light. This composite formation aimed to extend the light absorption capabilities to a broader range and facilitate more efficient charge carrier dynamics. Extensive characterization methods, including SEM, FT-IR, XRD, EDS, TEM, and UV–Vis spectrophotometry, were employed to assess the morphology, structural, and optical properties of the synthesized nanocomposites. Sample S6 showed the highest photocatalytic performance towards methylene blue, reaching a methylene blue degradation rate of 83% in 60 min of visible light exposition (300 W xenon lamp, λ > 420 nm) among the samples studied. The best performance of Sample S6 can be explained by its homogenous morphology and promoted charge carrier dynamics, while the lower efficiency of other samples is probably due to agglomeration and partial light absorption. The superior photocatalytic activity of Sample S6 is attributed to the plasmonic contribution of silver, which intensifies the interaction between light and the nanocomposite, as well as the effective separation of photogenerated electron–hole pairs. These findings therefore show the effectiveness of plasmonic nanocomposites in the degradation of organic pollutants in water, hence a robust solution for environmental remediation. The combination of plasmonic silver with semiconductor oxides significantly enhances the photocatalytic performance in the visible region.