Defect equilibria and partial molar properties of (La,Sr)(Co,Fe)O3−

Using in situ X-ray absorption spectroscopy to study the local structure and oxygen ion conduction mechanism in (La0.6Sr0.4)(Co0.2Fe0.8)O3−δ

“…The electric conductivity, stability, oxygen non-stoichiometry, and thermal expansion coefficients of perovskite oxides are affected by the B site, and these properties can be improved by B site transition metal doping. These properties are also sensitive to the oxygen content, which affects the B site atom [2,[4][5][6][7][8][9]. Understanding the oxygen ion conduction mechanism for cathode materials in SOFCs is key to investigating the valence and oxygen content, which varies with the oxygen partial pressure (P(O 2 )) and temperature.…”

Surface-Related Effects Limiting the Performance of Solid Oxide Fuel Cell Cathodes

“…The electronic conductivity of the sample was monitored as a function of time using a combined current source and voltmeter (Keithley, model 2400) with a computer controlled data acquisition system. The electronic conductivity σ of the perovskite-type oxides (La,Sr)(Co,Fe)O 3-δ is a function of the oxygen partial pressure and temperature 10 . Thus, at constant T, a small step-wise change of the p(O 2 ) in the reactor will lead to a relaxation of σ over time towards a new equilibrium state.…”

“…By contrast, the compounds of the series (La,Sr)(Co,Fe)O 3-δ exhibit both a high electronic conductivity and a significant ionic conductivity, correlated to the high oxygen nonstoichiometry δ [9][10][11] . Depending on chemical composition, temperature and p(O 2 ), up to 10 % vacancies can be accommodated in the oxygen sublattice.…”

Effects of preparation methods on the oxygen nonstoichiometry, B-site cation valences and catalytic efficiency of perovskite La0.6Sr0.4Co0.2Fe0.8O3−δ

“…the Sr (A-site cation) content, the B-site cation valence state and surrounding environment (temperature and oxygen partial pressure) [3,[27][28]. The oxygen vacancy concentration (½V :: o ) determined by d is an important parameter which is associated with many important properties including ionic/electronic conductivity, oxygen transport behavior and catalytic activity.…”

“…However, due to the temperature refection delay by the thermocouple signaling, the real temperatures for these two powders during combustion may be far higher than that. Previous work indicated that higher concentration of fully oxidized transition metal sites in the perovskite would increase the number of active constituents involved in the catalytic decomposition of H 2 O 2 [26][27][28][29][30]. During the decomposition process, the electron is transferred from the B-site ion to an oxidized site on the surface of the catalyst to produce HO 2 À radical.…”