Evaluation of Physicochemical Properties of Cadmium Oxide (CdO)-Incorporated Indium–Tin Oxide (ITO) Nanoparticles for Photocatalysis

This study investigates the structural, optical, and photocatalytic properties of cadmium oxide (CdO) nanoparticles (NPs) and indium–tin oxide (ITO)-doped CdO NPs. The synthesis of CdO NPs and ITO NPs was accomplished through the co-precipitation method. Scanning electron microscopy (SEM) analysis indicates that pure CdO NPs exhibit agglomerated structures, whereas ITO doping introduces porosity and roughness, thereby improving particle dispersion and facilitating electron transport. Energy dispersive spectroscopy (EDS) corroborates the successful incorporation of tin (Sn) and indium (In) within indium–tin oxide (ITO)-doped cadmium oxide (CdO) nanoparticles (NPs) in addition to cadmium (Cd) and oxygen (O). X-ray diffraction (XRD) analysis demonstrates that an increase in ITO doping results in a reduction of the crystallite size, decreasing from 23.43 nm for pure CdO to 18.42 nm at a 10% doping concentration, which can be attributed to lattice distortion. Simultaneously, the band gap exhibits a narrowing from 2.92 eV to 2.52 eV, achieving an optimal value at 10% ITO doping before experiencing a slight increase at higher doping concentrations. This tuneable band gap improves light absorption, which is crucial for photocatalysis. The photocatalytic degradation of rhodamine B (RhB) highlights the superior efficiency of ITO-doped CdO nanoparticles, achieving a remarkable 94.68% degradation under sunlight within 120 min, up 81.01%, significantly surpassing the performance of pure CdO. The optimal RhB concentration for achieving maximum degradation was determined to be 5 mg/L. This enhanced catalytic activity demonstrates the effectiveness of ITO-doped CdO NPs under both UV and visible light, showcasing their potential for efficient pollutant degradation in sunlight-driven applications.