Synthesis, Electrical Properties and Chemical Stability of BaCe0.7In0.3-xGdxO3-δ

Abstract

In3+, Gd3+ were selected as substitution elements for Ce4+ in order to increase electrical conductivity and chemical stability of BaCeO3. A modified sol-gel method was used to fabricate BaCe0.7In0.3-xGdxO3-δ (x = 0, 0.1, 0.2, 0.3) nanopowders. XRD results indicated that the diffraction angle moved to lower with increase of the Gd3 + doping concentration, so that the interplanar spacing gradually increased. The impedance spectra analysis showed that conductivity first increased (x = 0~0.2) and then decreased with the Gd3 + doping increase. The total conductivities at 800oC were 3.8 × 10-3 S·cm-1 (x = 0), 8.0 × 10-3 S· cm-1 (x = 0.1), 2.5 × 10-2 S· cm-1 (x = 0.2), 1.36 × 10-2 S ·cm-1 (x = 0.3). Chemical stability test in CO2 show that all samples except for x=0.3 sample calcination at 800oC for 2h under 100% CO2 and x=0, 0.1 samples heating in boiling water for 12h kept main perovskite structure. Therefore, x=0.1 sample show better electrical conductivity and chemical stability.