Structural and physical-chemical characterization of redox active CeOnanoparticles synthesized by precipitation in water-alcohol solutions.

A set of cerium dioxide nanoparticles (CeONPs) 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 CeONPs is controlled largely by the dielectric constant of the reaction solution. An increase of the percentage of Ceions at the surface was observed with a concomitant reduction of the NP sizes. All synthesized CeONPs possess relatively high positive values of zeta-potential ( > 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 CeONPs is higher at a low percentage of Ceat the NP surface. In contrast, smaller CeONPs with a higher percentage of Ceat the NP surface display a higher oxidase-like activity.