The structures and ionic conductivities of Ce1-xLaxO2 solid solutions, where x was between 0 and 0.3, were investigated. The samples were prepared hydrothermally for the first time. The uniformly small particle size (25 to 50nm) of the hydrothermally prepared materials permitted sintering of the samples into highly dense ceramic pellets at 1300 to 1400C (as compared with the usual temperatures of 1600 to 1650C for solid-state techniques). The solubility limit of La2O3 was determined to be around 20mol%. The highest conductivity, of 6.4 x 10-3S/cm (activation energy: 0.73eV), was found for x = 0.15.

Hydrothermal Synthesis and Properties of (Ce,La)O2 Solid Solutions. S.Dikmen, P.Shuk, M.Greenblatt: Solid State Ionics, 1999, 126[1-2], 89-95