Papers by Keyword: CeO₂-ZrO₂

Abstract: A novel surfactant-assisted synthesis method was developed in our laboratory to enhance the oxygen storage capacity (OSC) and the thermo stability of a TWC catalyst based on zirconia and rare earth oxides. The same procedure was used to prepare ceria-zirconia compositions with different amount of ceria, either undoped or doped with La and Nd. The potential use of these materials in a two steps solar thermochemical water splitting cycle for the production of H₂ was investigated. For this proposal the O₂ release of the materials was measured through thermogravimetric analysis in N₂ at 1573K. Then all prepared compositions were subjected to an aging treatment at temperature above 1573K in air or in N₂ flow and their activity in producing H₂ via water splitting at 1073K was evaluated with respect their structural evolution. The results obtained highlight that the reactivity depends on the temperature and atmosphere of the treatments and on the composition. The best result was obtained for the ceria rich composition treated at 1573K in N₂ and for the corresponding doped composition treated in air.

Abstract: 12 mol%CeO2 based composites were fabricated by a pressureless sintering technique and post-HIP treatments. The mixture of 12CeO2-ZrO2/3Y2O3-ZrO2 (= 80 wt%/20 wt%) powders from various methods were prepared by a ball milling technique and consequently sintered at 1400
in air atmosphere and post-HIP treatment at 1350
. The 12Ce-ZrO2/Y-ZrO2 composites sintered from mixture of 12CeO2-ZrO2 powder and 3Y2O3-ZrO2 powders possessed the high strength over 1300 MPa and also high fracture toughness over 11 MPam1/2. Furthermore, the significant inhibition of the ZrO2 phase transformation of tetragonal to monoclinic phase under an aqueous hydrothermal condition at 150
was obtained for these 12Ce-ZrO2/Y-ZrO2 composites prepared from this method. Microstructural observation was in detail performed by TEM and EDS.