High-Resolution Thermochemical Study of Phase Stability and Rapid Oxygen Incorporation in YBaCo4–xZnxO7+δ 114-Cobaltites,The Journal of Physical Chemistry A

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High-Resolution Thermochemical Study of Phase Stability and Rapid Oxygen Incorporation in YBaCo4–xZnxO7+δ 114-Cobaltites
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2018-11-15 00:00:00 , DOI: 10.1021/acs.jpca.8b08987
D. S. Tsvetkov ₁ , P. S. Maram _{2,

3} , N. S. Tsvetkova ₁ , A. Yu. Zuev ₁ , A. Navrotsky ₂

Affiliation

The formation thermodynamics of YBaCo_4–xZn_xO_7+δ (x = 0, 1, and 3) oxides was determined by high-temperature oxide melt solution calorimetry. All of the studied oxides are thermodynamically metastable due to the tendency of cobalt to increase the oxidation state under oxidizing conditions as well as to significant bond valence sum mismatch for Ba and Y in 114-oxides. Complex phase evolution in YBaCo₄O_7+δ at 350–400 °C upon oxygen absorption was revealed using incremental precise oxygen dosing. The calorimetric results support phase changes seen during in situ X-ray diffraction structural studies and provide high-resolution measurement of the amount and energetics of oxygen absorbed by YBaCo_4–xZn_xO_7+δ under equilibrium conditions.

中文翻译：

在YBaCo相稳定性和快速氧结合的高分辨率热化学研究_{-4- X}的Zn _X ö _{7 +δ} 114-辉钴矿

YBaCo _{4– x} Zn _x O _{7 +δ}（x = 0、1和3）氧化物的形成热力学是通过高温氧化物熔融溶液量热法确定的。由于钴在氧化条件下会增加氧化态的趋势，以及在114个氧化物中Ba和Y的键合价和不匹配，因此所有研究的氧化物都是热力学亚稳态的。YBaCo ₄ O _{7 +δ中的}复杂相演化在350–400°C时，使用增量式精确氧气定量显示了氧气吸收。量热结果支持在原位X射线衍射结构研究中看到的相变，并提供了在平衡条件下YBaCo _{4– x} Zn _x O _{7 +δ}吸收的氧气量和能量的高分辨率测量。

更新日期：2018-11-15

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