Oxygen and electron transport in Ce0.1Sr0.9FeO3−δ

Ce0.1Sr0.9FeO3−δ was synthesized via a solid-state reaction in air and confirmed to be single-phase with the cubic perovskite structure (SG Pm3¯m). The oxygen content variation in the oxide was measured by a thermogravimetric technique in air from room temperature to 950 °С, and by a coulometric titration at 950 °С in the range of oxygen partial pressure (pO2) from 10−15 atm to 0.5 atm. Electrical conductivity (σ) was measured by a four-probe dc technique in the pO2 interval of 10−18–0.5 atm at 750–950 °С. Partial contributions to total conductivity from oxygen ions, electrons, and holes were separated, based on their different dependence on oxygen partial pressure. The obtained data were used to estimate oxygen flux density (jO2) through the oxide membrane. The obtained characteristics were compared with those of La0.5Sr0.5FeO3−δ as the most promising ferrite for an oxygen membrane material. While oxygen-ion and hole conductivity were higher in La0.5Sr0.5FeO3−δ, Ce0.1Sr0.9FeO3−δ had higher electron conductivity. Though oxygen flux density 8 ml·cm−2 min−1, calculated for a membrane of Ce0.1Sr0.9FeO3−δ under partial methane oxidation conditions was ~25% lower than that for La0.5Sr0.5FeO3−δ it characterized this oxide as a promising membrane material. •Oxygen non-stoichiometry and transport properties of Ce0.1Sr0.9FeO3−δ are studied.•Cerium introduction increases oxygen deficiency in SrFeO3−δ under ambient conditions.•The n-type conductivity in Ce0.1Sr0.9FeO3−δ is 50% higher than that in SFeO3−δ.•The Ce0.1Sr0.9FeO3−δ membrane should give an oxygen flux density of 8 ml·min−1 cm−2.