Bio-ethanol obtained from biomass has been suggested as a promising renewable source of H2. It is a challenge to find low-cost catalysts (without noble metals) able to break the C-C bond of ethanol at low temperature. A CeNiHZOY catalyst was recently found to convert ethanol at 60 °C only, by steam reforming coupled with partial oxidation [8]. The distribution of products is similar to what is obtained by steam reforming at high temperatures: H2 (about 45 %) and mainly CO2 and CO. The reaction is initiated at 230 °C, but the temperature increases after a short induction period so that a temperature of 60 °C is sufficient to maintain the reaction. This is explained by the occurrence of two exothermic reactions: (i) between hydride species

of the catalyst and O2, and (ii) between ethanol and O2 (partial oxidation). The reaction is sustainable because hydride species are replaced and provided by ethanol.

A pre-treatment at 250 °C under H2 is necessary to obtain the active catalyst, which is an oxyhydride. As in the case of copper chromite, large quantities of hydrogen can be stored in CeNiXOY mixed oxides. H2 is heterolytically dissociated at an anionic vacancy and an O2- species of the catalyst. The insertion of hydride species in the solid was evidenced by INS. The spectra of CeNi1OY and CeNi0.5OY are shown in Fig. 2.2. The INS spectrum of the solid treated in vacuum at 200 °C, which contains OH groups, has been subtracted. The peak at about 460 cm-1 was assigned to hydrides and the band around 870 cm 1 to H adsorbed on metallic Ni particles, because the band intensity decreases when the Ni loading is decreased. While the assignment of the first peak appears to be reliable (after re-oxidation, this peak disappears whereas a band corresponding to OH groups emerges around 630 cm 1), the assignment of the higher frequency band to p3-H species on Ni0 particles is less certain, and the contribution from OH groups cannot be excluded.