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首页> 外文期刊>Journal of Materials Chemistry, A. Materials for energy and sustainability >Tuning oxygen content and distribution by substitution at Co site in 112 YBaCo2O_(5-δ): impact on transport and thermal expansion properties
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Tuning oxygen content and distribution by substitution at Co site in 112 YBaCo2O_(5-δ): impact on transport and thermal expansion properties

机译：通过在112 YBaCo2O_（5-δ）中的Co位置进行取代来调节氧含量和分布：对传输和热膨胀性能的影响

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摘要

Polycrystalline "112" ordered oxygen deficient double perovskites YBaCo_(2-x)Me_xO_(5+δ) (Me = Fe, Cu, Ni) were synthesized by a glycerol-nitrate route with 0.0 ≤ x ≤ 0.7 for Me = Fe, 0.0 ≤ x ≤0.6 for Me = Cu and x = 0.1 for Me = Ni. The combined X-ray diffraction, electron microscopy and thermo-gravimetric studies show that all these oxides exhibit the a_p x a_p x 2a_p tetragonal structure (S.G. PAImmm); moreover, the oxygen content increases continuously with x in the iron-substituted oxide YBaCo_(2-x)Fe_xO_(5+δ) whereas the opposite is observed for the copper phase YBaCo_(2-x)Cu_xO_(5+δ). This difference, which is due to the more electropositive character of Fe~(3+) compared to Cu~(2+), is hindered in the Ni~(2+) case due to its inability to accommodate the pyramidal coordination. The changes of the conductivity of these compounds versus temperature are closely related to their oxygen loss, in agreement with a defect structure model suggested earlier. Thermal expansion measurements prove the absence of phase transition in alt oxides within the temperature range studied. The chemical compatibility of YBaCo_(1.4)Fe_(0.6)O_(5+δ) with the electrolyte Ce_(0.8)Sm_(0.2)O_(2-δ) is also demonstrated.
机译：通过硝酸甘油法合成了多晶“ 112”有序缺氧双钙钛矿YBaCo_（2-x）Me_xO_（5 +δ）（Me = Fe，Cu，Ni），其中Me = Fe，0.0≤x≤0.7对于Me = Cu，≤x≤0.6;对于Me = Ni，x = 0.1。 X射线衍射，电子显微镜和热重分析的结合表明，所有这些氧化物均表现出a_p x a_p x 2a_p四方结构（S.G. PAImmm）。此外，铁取代的氧化物YBaCo_（2-x）Fe_xO_（5 +δ）中的氧含量随x连续增加，而铜相YBaCo_（2-x）Cu_xO_（5 +δ）则相反。在Ni〜（2+）情况下，由于Fe〜（3+）与Cu〜（2+）相比具有更大的正电性，因此这种差异受到阻碍，因为它无法适应锥体配位。这些化合物的电导率随温度的变化与它们的氧损失密切相关，这与先前提出的缺陷结构模型一致。热膨胀测量结果证明在所研究的温度范围内，alt氧化物中不存在相变。还说明了YBaCo_（1.4）Fe_（0.6）O_（5 +δ）与电解质Ce_（0.8）Sm_（0.2）O_（2-δ）的化学相容性。

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