Series of solid solutions of (Ce0.85Sm0.15)1−xTbxO2−δ with x = 0 to 0.05 were synthesized by using the glycine–nitrate process. All of the prepared (Ce0.85Sm0.15)1−xTbxO2−δ (x = 0–0.05) powders were sintered at 1250, 1350 and 1450C, respectively. X-ray diffraction patterns indicated that all of the  samples crystallize to a single phase of cubic fluorite structure. Higher sintering temperature was found to give lower electrical conductivity and higher activation energy for (Ce0.85Sm0.15)1−xTbxO2−δ (x = 0–0.05). The lower sintering temperatures suppress grain growth giving rise to small grain size. The samples sintered at lower temperatures showed higher grain boundary conductivities, which results in the increasing of total electrical conductivity. The change of electrical conductivities of solid solutions for (Ce0.85Sm0.15)1−xTbxO2−δ (x  = 0–0.05) was not obvious, and the maximum conductivity was found at x = 0.01 when sintered at 1250C. The reason may be that co-doping 0.01 Tb into doped ceria will increase the O vacancy concentration slightly, increasing dopant concentration, the O vacancy Vo•• and the dopants TbCe’ and SmCe’ tended to associate and form [Vo••TbCe’] and [Vo••SmCe’] pairs, resulting in a decrease in [Vo••].

Effect of Tb Co-Dopant on the Electrical Conductivity of Sm-Doped Ceria Electrolyte. D.Yan, X.Liu, D.Xu, C.Zhu, W.Ma, J.Niu, Y.Liu, W.Su: Solid State Ionics, 2008, 179[21-26], 995-9