Structural, Morphological, Optical and Photocatalytic Properties of ZnO50%-CdO50% Mixed-Oxide Nanoparticles

This investigation explores the synthesis, comprehensive characterization, and photocatalytic performance of equimolar ZnO _50% -CdO _50% mixed-oxide nanoparticles prepared via sonochemical methodology with and without lemon extract capping. Structural analysis through X-ray diffraction revealed hexagonal wurtzite architecture with lattice parameters a = 3.861 Å and c = 5.220 Å for uncapped samples, indicating significant lattice distortion from Cd²⁺ incorporation. Morphological investigations using scanning electron microscopy and high-resolution transmission electron microscopy demonstrated average particle sizes of 62 nm and 48 nm respectively, with mixed cubic-spherical geometries evidencing solid solution formation. Lemon-capped nanoparticles exhibited reduced crystallite dimensions (17.03 nm) with enhanced dispersion and morphological uniformity. Optical characterization revealed band gap values approximating 2.8-3.0 eV, representing intermediate properties between constituent oxides. Photocatalytic evaluation against three organic pollutants demonstrated exceptional performance: 91.98% degradation efficiency for Methylene Blue, 88.27% for Crystal Violet, and 47.45% for tetrazine under UV irradiation over 165 minutes. The equimolar composition maximized heterojunction interface area, optimizing charge separation and reactive oxygen species generation. Lemon capping significantly enhanced catalytic activity through surface passivation and improved dispersion. These findings establish ZnO _50% -CdO _50% nanocomposites as promising materials for advanced oxidation processes in water treatment applications, with performance varying systematically based on pollutant electronic structure and degradation mechanism requirements.