Hydrogen storage in cerium nickel and zirconium (or aluminium) mixed oxides.

Interaction of hydrogen with a series of cerium nickel and zirconium (or aluminium) mixed oxides CeM0.5NiXOY (M = Zr or Al, 0 ´ x ´ 3) has been studied in the 50-800°C temperature range. Hydrogenation of 2-methyl-1,3-diene (isoprene) under helium flow in the absence of gaseous hydrogen is used to reveal and titrate reactive hydrogen species present in the solid previously treated under H2 at various temperatures. The CeM0.5NiXOY mixed oxides are large catalytic hydrogen reservoirs and among the solids studied, the highest amount of hydrogen (about 10 wt%) is stored in CeZr0.5Ni1OY pretreated in H2 at about 200°C. Compared to the binary mixed oxides CeNiXOY, the presence of M allows to increase the hydrogen storage and give a better stability to the system, in particular, with temperature. Different physico-chemical techniques (TPR, ATG ...) were used to characterize the solids studied