Ceramic oxides with high oxygen exchange: The system Sr–Co–O

Oxide compositions in the system Sr–Co–O were prepared by solid-state reaction. The oxide–oxygen reactions were investigated by thermo-gravimetric measurements. Equilibration was controlled by an amperometric lambda sensor. Thermodynamic data for the oxide–oxygen reaction were calculated. For the reaction CoO/Co3O4 with complete change of crystal structure between ferrite-and NaCl-types, the amount of oxygen exchanged (δ = 1), and the absolute values of changes in enthalpy and entropy are the highest. The lowest values were observed for the partial molar enthalpy of the solid-solution reaction of oxygen with the stable perovskite phase of Sr0.965Ce0.035CoO2.535+n.