Oxygen storage properties of hexagonal HoMnO3+δ.
Oxygen storage properties of hexagonal HoMnO3+δ.
复制标题
六方晶系HoMnO3+δ的储氧性能。
DOI：
10.1039/c7cp03556j
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Jeongsoo Kang
中科院分区：
文献类型：
--
作者：
K. Świerczek;Alicja Klimkowicz;Kengo Nishihara;Shuntaro Kobayashi;A. Takasaki;Maleeha Alanizy;S. Koleśnik;B. Dabrowski;Seungho Seong;Jeongsoo Kang
采用X射线衍射和热重分析方法，在氧气和空气中高温原位氧化和还原过程，研究了六方晶系HoMnO 3 +δ锰氧化物在钙钛矿相稳定边界处的结构和氧含量的变化。报道了由固态合成和高冲击机械研磨制备的材料在化学计量Hex 0和氧负载Hex 1相之间的结构转变过程中的储氧性能、转变温度和氧掺入和释放的动力学。长期退火实验表明，HoMnO 3 +δ 15 MM的Hex 0（δ = 0）→ Hex 1（δ = 0.28）相变受表面反应和新相形核的限制。Hex 0 ParticipHex 1转变的温度已经分别在290 °C和250 °C下以0.1° min-1的速率加热和冷却时建立，这也表明转变的温度滞后在平衡时可能小至10 °C。球磨HoMnO 3 +δ对提高氧气中还原/氧化过程的速度只有很小的影响，但重要的是，在长时间加热后，在220-255 °C的温度范围内，允许在空气中引入大量的氧气。载氧样品中Mn价态的Mn 2 p XAS结果支持TG法测定的氧含量。有效锰价的磁化率数据给出了不确定的结果，由于主导磁性的Ho 3+离子。HoMnO 3 +δ与DyMnO 3 +δ的比较表明，稀土离子尺寸的微小增加对六方锰氧化物的氧化还原性能有很大的影响，合成平均尺寸较大的（Y，Ln）MnO 3 +δ锰氧化物可以显著提高其实用性能。
Structural and oxygen content changes of hexagonal HoMnO3+δ manganite at the stability boundary in the perovskite phase have been studied by X-ray diffraction and thermogravimetry using in situ oxidation and reduction processes at elevated temperatures in oxygen and air. The oxygen storage properties during structural transformation between stoichiometric Hex0 and oxygen-loaded Hex1 phases, transition temperatures and kinetics of the oxygen incorporation and release are reported for materials prepared by the solid-state synthesis and high-impact mechanical milling. Long-term annealing experiments have shown that the Hex0 (δ = 0) → Hex1 (δ ≈ 0.28) phase transition is limited by the surface reaction and nucleation of the new phase for HoMnO3+δ 15MM. The temperatures of Hex0 ↔ Hex1 transitions have been established at 290 °C and 250 °C upon heating and cooling, respectively, at a rate of 0.1° min-1, also indicating that the temperature hysteresis of the transition could possibly be as small as 10 °C in the equilibrium. Ball-milling of HoMnO3+δ has only a small effect on improving the speed of the reduction/oxidation processes in oxygen, but importantly, allowed for considerable oxygen incorporation in air at a temperature range of 220-255 °C after prolonged heating. The Mn 2p XAS results of the Mn valence in oxygen loaded samples support the oxygen content determined by the TG method. The magnetic susceptibility data of the effective Mn valence gave inconclusive results due to dominating magnetism of the Ho3+ ions. Comparison of HoMnO3+δ with previously studied DyMnO3+δ indicates that a tiny increase in the ionic size of lanthanide has a huge effect on the redox properties of hexagonal manganites and that practical properties could be significantly improved by synthesizing the larger average size (Y,Ln)MnO3+δ manganites.
影响因子：
8.6
作者：
Abughayada, C.;Dabrowski, B.;Chmaissem, O.
通讯作者：
Chmaissem, O.