Unveiling the potential of NiO-ZnCo₂O₄ nano-composites: Electrical, optical, electrochemical and antibacterial investigation

Zinc Cobaltite (ZCO) and Nickel Oxide (NiO) nanoparticles (NPs) were synthesized using a sol-gel technique, and their composites with different weight ratios were prepared using a straightforward sonication method. The NiO and ZCO NPs had small crystallite size of 10 nm and 18 nm, respectively. According to the ultraviolet-visible (UV-Vis) spectra, pure NiO and ZCO NPs exhibited band gaps of ∼3.5 eV and 3.3 eV. Antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial strains was also tested for the composite counterpart and its equivalents. Compared to pure NPs, the composite of 30 % ZCO-NiO (NZ3) had higher antibacterial activity with zone of inhibition of ∼13 mm against E. coli. The electrical and electrochemical properties were also explored and it was found that the composite of 50 % ZCO-NiO (NZ5) shows high specific capacitance of 188 F/g.