Defect chemistry and high-temperature thermodynamics of PrBaCo2O6-δ
| Autor: | I.L. Ivanov, Dmitry S. Tsvetkov, Dmitry Malyshkin, Vladimir V. Sereda, Andrey Yu. Zuev, Antoine Maignan, Anton L. Sednev-Lugovets |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Chemistry
Enthalpy chemistry.chemical_element Thermodynamics 02 engineering and technology Calorimetry Partial pressure Atmospheric temperature range 010402 general chemistry 01 natural sciences Oxygen Heat capacity Atomic and Molecular Physics and Optics 0104 chemical sciences Differential scanning calorimetry 020401 chemical engineering General Materials Science 0204 chemical engineering Physical and Theoretical Chemistry Entropy (order and disorder) |
| Zdroj: | The Journal of Chemical Thermodynamics. 161:106523 |
| ISSN: | 0021-9614 |
| DOI: | 10.1016/j.jct.2021.106523 |
| Popis: | Using the drop calorimetry and differential scanning calorimetry (DSC), the enthalpy increments of pure PrBaCo2O6-δ double perovskite in air in the temperature range from 365.3 K to 1272.8 K were obtained. As-measured enthalpy increments corresponded to the constant pO2, but variable oxygen content in PrBaCo2O6-δ (isodynamical conditions). The defect structure analysis yielded the analytical expressions for the equilibrium oxygen partial pressure, log(pO2) = f(δ, T), and the partial molar enthalpy of oxygen, Δ h ¯ O = f(T, δ) in PrBaCo2O6-δ, both functions being valid in relatively wide temperature range. The value of Δ h ¯ O at 1273 K was assessed independently by means of direct oxidation of PrBaCo2O6-δ in the DSC setup, and was found to agree well with Δ h ¯ O calculated from the defect structure model and pO2 – T – δ diagram. The knowledge of Δ h ¯ O = f(T, δ) allowed recalculating the enthalpy increments for the sample with constant oxygen content, Δ 298.15 T H ∘ (PrBaCo2O5.77), which were fitted with a modified Einstein function. The smoothed values of Δ 298.15 T H ∘ , heat capacity Cp(T), and entropy increments Δ 298.15 T S ∘ were evaluated and tabulated for PrBaCo2O5.77 in the temperature range 350 ≤ T/K ≤ 1300. The results obtained can be used for calculating Δ 298.15 T H ∘ , Cp(T), and Δ 298.15 T S ∘ for PrBaCo2O6-δ with an arbitrary constant oxygen content. |
| Databáze: | OpenAIRE |
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