Structural, optical, and antibacterial characteristics of mixed metal oxide CdO–NiO–Fe2O3 nanocomposites prepared using a self-combustion method at different polyvinyl alcohol concentrations.

In this study, the impact of polyvinyl alcohol (PVA) concentration on the sizes of mixed metal oxide (MMO) CdO–NiO–Fe₂O₃ nanocomposites was investigated. The results showed major improvements in the structural and optical properties that promote antibacterial activity. Self-combustion was used to synthesize MMO nanocomposites. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy were used to analyze the structural properties of the prepared samples. The optical properties of the MMO nanocomposites were examined using a UV–Visible spectrophotometer and photoluminescence (PL) spectroscopy. XRD analysis revealed a face-centred cubic structure for the CdO and NiO phases, whereas γ-Fe₂O₃ had a cubic spinel crystalline structure. TEM analysis revealed that the size of the MMO nanocomposites increased from approximately 7.4–25.1 nm as the PVA concentration decreased from 0.05 to 0.0125 g/ml. Owing to the quantum confinement of MMO, the optical band gap values of the samples varied in relation to the PVA concentration. In this study, CdO–NiO–Fe₂O₃ nanocomposites were investigated for their antibacterial activities against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, and Moraxella catarrhalis). The results suggest that these materials are promising candidates for antibiotic applications. [ABSTRACT FROM AUTHOR]