Electrical conductivity and chemical stability of perovskite-type BaCe0.8-x Ti x Y0.2O3-δ

Abstract

Here we report the synthesis, chemical stability, and electrical conductivity of Ti-doped perovskite-type BaCe 0.8-x Ti x Y 0.2 O 3-δ (x=0.05, 0.1, 0.2, and 0.3; BCTY). Samples were synthesized by conventional solid state (ceramic) reaction from corresponding metal salts and oxides at elevated temperature of 1,300-1,500°C in air. The powder X-ray diffraction confirmed the formation of a simple cubic perovskite-type structure with a lattice constant of a=4.374(1), 4.377(1), and 4.332(1) Å for x=0.05, 0.1, and 0.2 members of BCTY, respectively. Like BaCe 0.8 Y 0.2 O 3-δ (BCY), Ti substituted BCTY was found to be chemically not stable in 100% CO 2 and form BaCO 3 at elevated temperature. The bulk electrical conductivity of BCTY decreased with increasing Ti content and the x=0.05 member exhibited the highest conductivity of 2.3×10 −3 S cm −1 at 650°C in air, while a slight increase in the conductivity, especially at low temperatures (below 600°C), was observed in humidified atmospheres.

Synthesis and properties of BaCe1−xYxO3−δ–BaWO4 composite protonic conductors

“…Incorporation of zirconium into the doped barium cerate results in improving the chemical and mechanical stability [20,21] but leads to decreasing of conductivity especially due to poor sinterability of barium zirconate. Similar results were obtained by doping BaCeO 3 with yttrium and titanium [22,23].…”

Advanced materials for SOFC application: Strategies for the development of highly conductive and stable solid oxide proton electrolytes

“…Materials of the same system with a wider yttrium concentration changes were studied by Talimi and Thangadurai [36]. Complex oxides were obtained by the aid of a solid phase synthesis at 1450°С for 24 h. Despite the fact that maximum synthesis temperature was the same as in the previous work [32], the BaCe 0.8-х Ti х Y 0.2 O 3-δ (х=0.05, 0.1, 0.2) materials crystallize into a cubic structure with unit cell parameters of 4.374, 4.377 and 4.332Å, respectively.…”

“…In addition, the conductivity in humid hydrogen is slightly lower than that in air. Based on the level of activation energy, calculated using conductivity dependencies on temperature, Talimi et al [36] concluded that the materials behaved like ionic-hole conductors in air and like co-ionic ones in humid hydrogen atmosphere. The influence of yttrium on the properties of barium cerate, containing small amount of titanium, was studied by Pasierb et al [37].…”

“…Electrical conductivity at 700°C and activation energy in the range of 450-700°C for BaCe 0.8-х Ti х Y 0.2 O 3-δ materials in air and wet H 2 atmospheres[36].…”

Effect of microstructure on chemical stability and electrical properties of BaCe0.9Y0.1O3 − δ

“…The thermodynamic data suggest that barium cerate is an unstable phase in the wide temperature range [11][12][13]. The ΔG of the reaction of barium carbonate formation (Eq.…”