International audienceThe textural and structural properties of high specific surface area (HS) CexZr1-xO2 mixed oxides (CeZrMO) and their modification upon thermal aging have been investigated. Results from BET area determination and complete porosity analysis, as well as high-resolution electron microscopy, XRD, Raman and FTIR spectroscopies are presented. Some relationships between the molar composition of the binary systems and their textural and structural properties are presented. In addition, it has been possible to propose an explanation for structural features of the mixed oxides (solid-solution structures and possible phase segregation) as a function of Ce content, a point of great interest for the knowledge of phase composition and stability of CeZrMO

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The objective of this study was to examine the mechanism of the reduction by hydrogen of ceria-zirconia (CZ) mixed oxides having a high BET surface area (100 m 2 g -1 ). Three methods were used in parallel to assess the Ce 3+ content, the surface and bulk oxygen vacancy concentrations, and the resulting oxygen storage capacity (OSC): temperature programmed reduction, Fourier transform infrared (FT-IR) measurements of methanol adsorbed on the reduced surfaces, and a Faraday microbalance to determine the magnetic susceptibility of the reduced oxides. The three methods conclude that the introduction of zirconium into the ceria lattice has a positive influence on the OSC. Compared to pure ceria, the CZ mixed oxides exhibit better redox properties, with a lower temperature of initial reduction and a higher reduction percentage for all compositions. The reducibility increases with the zirconium content, however the OSC per gram of solid is practically the same for Zr contents between 20% and 50%. The reduction process very rapidly involves the bulk, but a treatment at room temperature under oxygen of the reduced samples oxidizes them almost completely. However, the FT-IR results underline the differing behavior of ceria for the distinct surface and bulk reduction processes.

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The allylic hydroxylation of enones using dioxygen as the oxidant has been studied. The reaction was first examined in the absence of any catalyst, using β-ionone as a model substrate. Then a new copper-aluminium mixed oxide, Cu-Al Ox, was prepared and characterized in order to be used as a catalyst. This oxide showed good activity, and provided the corresponding γor ε-hydroxylated enones, starting from different α,βor α,β,γ,δ-unsaturated ketones. In all cases, the [a]

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