Effect of Ag content on the nanostructure and antimicrobial activity of CeO₂

The morphological and antibacterial effects of CeO₂ nanoparticles (NPs) with different amounts of Ag precursor were studied. The samples were synthesized with different percentages of silver nitrate content by co-precipitation method. The cerium nitrate hexahydrate was a precursor of Ce reagent, polyvinylpyrrolidone as dispersant agent, and ammonium hydroxide as a precipitating agent. The obtained particles were annealed at 400 °C and characterized by X-ray diffraction, scanning electron microscope (SEM), transmission electron microscopy (TEM), and N₂ physisorption. The particles show high crystallinity, whose size decreases slightly by the effect of Ag precursor incorporation. These particle morphologies studied by SEM and TEM revealed the spherical shape of CeO₂ NPs. Furthermore, the Ag particles were observed with a size of around 30 nm. Selected area electron diffraction patterns confirm the cubic structure of CeO₂, also the cubic structure of Ag particles. Besides, it was determined that Ag incorporation has no significant influence on the textural properties of NPs. In addition, the antibacterial activity was evaluated against gram-negative and gram-positive microorganisms. The quantitative results showed that the antimicrobial activity increased depending on the Ag amount incorporated, reaching up to 99.999% of the growing reduction rate.