Structure and electrical conductivity of BaCe0.85Ln0.15O3−δ (Ln = Gd, Y, Yb) ceramics

Abstract BaCe 0.85 Ln 0.15 O 3− δ (Ln = Gd, Y, Yb) ceramics are synthesized by the solid state reaction method. All of BaCe 0.85 Ln 0.15 O 3− δ ceramics are composed of a single perovskite-type phase. The grain size of BaCe 0.85 Ln 0.15 O 3− δ (Ln = Gd, Y, Yb) ceramics decreases with decreasing the ionic radius of doped cations. BaCe 0.85 Y 0.15 O 3− δ ceramic has the highest total conductivity at 1073 K in both 4% H 2 O-saturated H 2 and air among three kinds of BaCe 0.85 Ln 0.15 O 3− δ ceramics. Total conductivities of BaCe 0.85 Gd 0.15 O 3− δ and BaCe 0.85 Y 0.15 O 3− δ ceramics exceed 0.01 S cm −1 in both 4% H 2 O-saturated H 2 and air above 773 K. The pre-exponential factors and activation energies of BaCe 0.85 Ln 0.15 O 3− δ ceramics are similar both in 4% H 2 O-saturated H 2 and in air. The crystal structure, relative density and grain boundary area are the main influencing factors on electrical conductivity of doped barium cerates.