Structural and physical-chemical characterization of redox active CeO₂nanoparticles synthesized by precipitation in...

A set of cerium dioxide nanoparticles (CeO₂NPs) was synthesized by precipitation in water-alcohol solutions under conditions when the physical-chemical parameters of synthesized NPs were controlled by changing the ratio of the reaction components. The size of CeO₂NPs is controlled largely by the dielectric constant of the reaction solution. An increase of the percentage of Ce³⁺ions at the surface was observed with a concomitant reduction of the NP sizes. All synthesized CeO₂NPs possess relatively high positive values of zeta-potential (ζ > 40 mV) suggesting good stability in aqueous suspensions. Analysis of the valence- and size-dependent rate of hydrogen peroxide decomposition revealed that catalase/peroxidase-like activity of CeO₂NPs is higher at a low percentage of Ce³⁺at the NP surface. In contrast, smaller CeO₂NPs with a higher percentage of Ce³⁺at the NP surface display a higher oxidase-like activity.