کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7745322 | 1498255 | 2016 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Oxygen nonstoichiometry and thermodynamic quantities in the Ruddlesden-Popper oxides LaxSr3 â xFe2O7 â δ
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
الکتروشیمی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Oxygen nonstoichiometry and thermodynamic quantities in the Ruddlesden-Popper oxides LaxSr3 â xFe2O7 â δ Oxygen nonstoichiometry and thermodynamic quantities in the Ruddlesden-Popper oxides LaxSr3 â xFe2O7 â δ](/preview/png/7745322.png)
چکیده انگلیسی
Oxygen nonstoichiometry in the Ruddlesden-Popper type oxides LaxSr3 â xFe2O7 â δ (x = 0, 0.25 and 0.5) was determined by means of the high temperature gravimetry and the coulometric titration. The measurements were carried out in the temperature range between 773 and 1073 K and the P(O2) range between 10â 40 and 1 bar. The P(O2) dependencies of the oxygen nonstoichiometry exhibited typical plateaus at δ ~ 1.0 for Sr3Fe2O7 â δ, δ ~ 0.875 for La0.25Sr2.75Fe2O7 â δ and δ ~ 0.75 for La0.5Sr2.5Fe2O7 â δ, where the average oxidation state of iron is 3 +. In the LaxSr3 â xFe2O7 â δ series, La0.5Sr2.5Fe2O7 â δ showed the smallest oxygen nonstoichiometry and was the most thermochemically stable compound against on P(O2), temperature, and the La content. Thermodynamic quantities of the partial molar enthalpy of oxygen, hO â hO°, and the partial molar entropy of oxygen, sO â sO°, were calculated from measured nonstoichiometric data. The behavior of oxygen nonstoichiometry and thermodynamic quantities indicates that the ideal-solution-like defect formation is established (La,Sr)3Fe2O7 in the oxygen deficient region.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Ionics - Volume 288, May 2016, Pages 298-302
Journal: Solid State Ionics - Volume 288, May 2016, Pages 298-302
نویسندگان
Yihan Ling, Fang Wang, Yusuke Okamoto, Takashi Nakamura, Koji Amezawa,