The evolution of plutonium dioxide surface due to water adsorption seems to influence H2 generationthrough the radiolysis of adsorbed water. Surface evolution of ceria, a non-radioactive surrogate for plutoniumdioxide, was investigated using Inverse Gas Chromatography (IGC), Raman spectroscopy, EnvironmentalScanning Electronic Microscopy (ESEM) and Atomic Force Microscopy (AFM). IGC highlightsthe complexity of ceria surface revealing three different adsorption sites on surface and indicate a surfaceevolution upon hydration. Thermal treatment appears to regenerate at least partially the initial surfacestate before hydration. IGC points out the influence of calcination temperature of ceria precursor on surfacereactivity. The nature of surface modification was investigated by Raman spectroscopy which suggestsformation of superficial hydroxide layer. ESEM and AFM were used to study potential surfacetopology modification upon superficial layer formation. Cerium hydroxide forms as a superficial layerwith a nanostructure differing from the one of the oxide.