Microstructural, Optical, and Antimicrobial Activity of ZnO-CuO NCP Prepared Using Co-precipitation Technique

Abstract

ZnO-CuO nanocomposite particles (NCPs) were synthesized at different molar ratios (4:1, 3:2, and 1:4) through the use of the co-precipitation technique, which produced interesting modifications in the particle’s physical characteristics. XRD showed that average crystallite size (D_avg) decreased noticeably from about 22.07 to 15.98 nm as the concentration of CuO increased within the ZnO matrix. This pattern points to a major impact of CuO content on the composite’s structural properties. Fourier-transform infrared spectroscopy (FTIR), two distinct functional groups were identified: v₁ and v₂, which were detected at approximately 524 cm⁻¹ and 427 cm⁻¹, respectively, and were linked to intrinsic and extrinsic vibrations. These spectral characteristics highlight the complex interaction between ZnO and CuO and offer important insights into the chemical bonding and molecular interactions within the composite system. The ZnO-CuO nanocomposite was subjected to field emission scanning electron microscopy and energy-dispersive X-ray analysis (SEM-EDX) which showed spherical shapes with increments in agglomeration. UV-Vis absorption spectra revealed a blue shift with increasing absorption in the UV region. The energy band gap of ZnO in its pristine state was found to be 3.31 eV, but in the ZnO₄-CuO₁ composition, it increased to 5.48 eV, suggesting that the addition of CuO caused a significant change in the electronic structure. Significantly, ZnO-CuO NCP antimicrobial evaluation demonstrated exceptional antibacterial efficacy against bacterial strains that were both Gram positive and Gram negative, in addition to fungal pathogens. This strong antimicrobial activity highlights the synthetic nanocomposite’s potential use in fighting a range of microbial infections and highlights their bright future in the environmental and biomedical fields.