Zn doped CdO nanoparticles: Structural, morphological, optical, photocatalytic and anti-bacterial properties

Pure and zinc-doped CdO NPs (Zn-CdO NPs) were synthesized through a facile co-precipitation method. The structural, morphology, chemical composition, optical and antibacterial activity of the NPs were studied with respect to pure and Zn-doped CdO concentration (0-7.5mol.%). Scanning electron microscope (SEM) images reveal that pure and Zn-doped CdO NPs were in the nano-scale regime with different crystalline morphology. The energy dispersive X-ray spectroscopy (EDS) spectrum predicts the presence of Cadmium (Cd), Zinc (Zn) and Oxygen (O) in the prepared samples. Optical studies divulge that Zn²⁺ doping CdO decreases the band gap energy (Eg) (3.36-3.02eV) with an increase in Zn²⁺ doping concentration. Optical absorption spectrum of CdO red-shifted as the Zn concentration varied from 2.5mol.% to 7.5mol.%. PL spectra displayed a strong UV emission peak at 380nm. Enhanced Visible emission at 430 and 522nm with Zn²⁺ doping interprets the defect density in CdO by occupying Cd²⁺ vacancies with Zn²⁺ ions. Photocatalytic studies revealed that 7.5% Zn-doped CdO NPs show maximum degradation for atrazine (ATZ) as herbicide pollution under UV irradiation. Antibacterial studies against (Gram positive) and (Gram negative) bacteria's authenticate that Zn²⁺ doped CdO nanostructures exhibit excellent antibacterial activity against all bacteria's with an increase in doping concentration.