Synthesis and oxygen transport properties of La0.2Sr0.8Fe1−xTixO3−δ (x = 0.2, 0.4) intended for syn-gas production

Perovskites in the system La0.2Sr0.8Fe1−xTixO3−δ exhibit high stability at severe reducing conditions and high temperatures. Here we report the processing and oxygen transport properties of two compositions: La0.2Sr0.8Fe1−xTixO3−δ (x = 0.2, 0.4). Single-phase powders were synthesized by spray pyrolysis (SP) and solid state reaction (SSR). The resulting average particle sizes (BET) ranged from 140 nm (SP) to 1090 nm (SSR). Samples were prepared by CIP and pressureless sintered between 1200 and 1250 °C for 8–12 h. Sintered densities ranged from 97 (SSR) to 99% (SP) and grain size was less than 1.5 μm. The average TEC varied in the range (13.8–14.6) × 10−6 K−1 at 300–600 °C and (21.3–28.9) × 10−6 K−1 at 600–800 °C. Surface exchange coefficients (kchem) and bulk diffusion coefficients (Dchem) in terms of temperature and pO2pO2 were assessed by the method of electrical conductivity relaxation. A simple defect model was applied to explain electrical conductivity and bulk diffusion behaviour.