Charge distribution in U1-xCexO2+y nanoparticles

In view of a safe management of the nuclear wastes, a sound knowledge of the atomic-scale properties of U1-xMxO2+y nanoparticles is essential. In particular, their cation valences and oxygen stoichiometries are of great interest as these properties drive their diffusion and migration behaviour into the environment. Here, we present an in-depth study of U1-xCexO2+y, over the full compositional domain, by combining XRD and HERFD-XANES. We show on one hand the co-existence of UIV, UV and UVI and on the other hand that the fluorite structure is maintained despite this charge distribution.