Investigation into oxide vacancy ordering in the Ce1-xLnxO2-x/2 (Ln = La and Nd, x= 0.4 and 0.6) system, materials for hydrogen production

La-doped CeO2 materials are of great interest because of their possible use in high temperature electrochemical devices for energy production and storage, such as membranes for hydrogen production and solid oxide fuel cells.However, there is a significance controversy regarding the crystalline structure of these materials and its relation with their electrical properties, where different authors report divergent results. In our work, we found out that in CeO2 systems doped with low contents of lanthanum, a simple structure was stabilized, where for higher lanthanum contents a different one was formed, due to an ordering of the oxide vacancies of the material.Neutron studies, at room and high temperature, are key to understand the changes in structure of these materials, as well as their behaviour on heating, where changes in symmetry are observed,