Correlation between thermodynamic and thermomechanical quantities of selected perovskite-type oxides

<i>In Situ</i> and Simultaneous Observation of Palladium Redox and Oxygen Storage/Release in Pd/Sr&ndash;Fe&ndash;O Perovskite Catalysts Using Dispersive XAFS

“…However, the amount of palladium-doping is small (3.0 mass%), and the change in the density cannot be explained only by the change between Pd 0 and Pd 21) The observed change in the density can be concluded to indicate the change in the oxygen deficiency ¤ that is located in the perovskite-type SrFeO 3¹¤ or Sr 4 Fe 6 O 13¹¤ . Thus, it can also be concluded that we succeeded in the simultaneous observation of the redox reaction of palladium and the oxygen storage/release process during redox-gas cycles using dispersive XAFS with a time resolution of less than 20 ms, when we measured the change in absorbance at an energy lower than the edge energy, as well as the change in the XANES and EXAFS spectra.…”

Synchrotron Radiation Shed Light to <i>In Situ </i>and Dynamic Observation of High-Temperature Processes

“…The reversible change in the density can be attributed to the change in the density of the Sr-Fe-O oxides. It is reasonable to consider that the density change during the redox cycles is caused by chemical expansion and contraction of the perovskite-type SrFeO 3−δ and Sr 4 Fe 6 O 13−δ phases in response to changes in the oxygen deficiency (δ), which is typically found in oxides with perovskite-type structures, such as La 1−x Sr x MnO 3+δ [29], SrCo 0.9 Nb 0.1 O 3−δ [30], Nd 2−x Sr x NiO 4+δ [31], and Ca 0.5 Sr 0.5 Mn 1−b Fe b O 3−δ [32]. The observed change in the normalized density, ρ norm , can be concluded to indicate the change in the oxygen deficiency δ that is located in the perovskite-type SrFeO 3−δ or Sr 4 Fe 6 O 13−δ .…”