Engineering the defect state and reducibility of ceria based nanoparticles for improved anti-oxidation performance

Abstract

Due to their excellent anti-oxidation performance, CeO₂ nanoparticles receive wide attention in pharmacological application. Deep understanding of the anti-oxidation mechanism of CeO₂ nanoparticles is extremely important to develop potent CeO₂ nanomaterials for anti-oxidation application. Here, we report a detailed study on the anti-oxidation process of CeO₂ nanoparticles. The valence state and coordination structure of Ce are characterized before and after the addition of H₂O₂ to understand the anti-oxidation mechanism of CeO₂ nanoparticles. Adsorbed peroxide species are detected during the anti-oxidation process, which are responsible for the red-shifted UV-vis absorption spectra of CeO₂ nanoparticles. Furthermore, the coordination number of Ce in the first coordination shell slightly increased after the addition of H₂O₂. On the basis of these experimental results, the reactivity of coordination sites for peroxide species is considered to play a key role in the anti-oxidation performance of CeO₂ nanoparticles. Furthermore, we present a robust method to engineer the anti-oxidation performance of CeO₂ nanoparticles through the modification of the defect state and reducibility by doping with Gd³⁺. Improved anti-oxidation performance is also observed in cell culture, where the biocompatible CeO₂-based nanoparticles can protect INS-1 cells from oxidative stress induced by H₂O₂, suggesting the potential application of CeO₂ nanoparticles in the treatment of diabetes.