Harnessing Co₃O₄/Ag₂MoO₄/CeO₂ ternary nanocomposites for solar light-induced degradation of anthropogenic dye...

A Co₃O₄/Ag₂MoO₄/CeO₂ternary nanocomposites photocatalyst was successfully synthesized through a straightforward ethanol-assisted chemical method. Comprehensive characterization of its structural and optical properties was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) analysis. XRD analysis confirmed the presence of Co₃O₄, Ag₂MoO₄ and CeO₂ in the ternary composite sample. SEM and TEM analyses confirmed a strong interfacial interaction among Co₃O₄, Ag₂MoO₄, and CeO₂ in the ternary nanocomposite. The integration of Co₃O₄ and Ag₂MoO₄into the CeO₂ matrix resulted in a significant narrowing of the band gap from 2.32 to 1.5 eV, thereby improving photoinduced charge separation and enhancing light absorption in the visible range. When exposed to solar irradiation, the Co₃O₄/Ag₂MoO₄/CeO₂ ternary nanocomposites exhibited outstanding photocatalytic performance, achieving up to 98% degradation of methylene blue (MB) within 90 min. This superior activity is primarily ascribed to the effective suppression of electron-hole recombination, with CeO₂ acting as a key component in facilitating charge carrier mobility and improving overall photocatalytic efficiency. Moreover, the ternary nanocomposites effectively degraded a binary dye system comprising cationic methylene blue dye (MB dye) and anionic methyl orange (MO), showcasing its versatility in treating mixed dye pollutants. The synergistic interaction among the three components was instrumental in achieving high degradation rates in both single and mixed dye systems. In addition to its high photocatalytic activity, the Co₃O₄/Ag₂MoO₄/CeO₂ ternary nanocomposites exhibited strong structural stability, was easily recoverable, and maintained its performance over multiple cycles, highlighting its practical potential for environmental applications. The proposed photocatalytic degradation mechanism, supported by radical scavenging experiments, revealed that both superoxide (^·O₂⁻) and hydroxyl (^·OH) radicals played dominant roles in the breakdown of dyes in both individual and binary systems. These findings suggest that the developed ternary photocatalyst not only holds promise for efficient degradation of tetracycline under natural sunlight but also meets critical criteria for treating antibiotic contaminants in pharmaceutical wastewater and applications in solar-driven environmental remediation.