确定动力参数和确定氧气交换过程中对LaNi0.6Fe0.4O3-的速度决定步骤
Natalia Porotnikova1, Dmitriy Zakharov1, Anna Khodimchuk1,2
1Laboratory of Kinetics, The Institute of High-Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences, 20 Akademicheskaya Street, Yekaterinburg 620137, Russia.
International journal of molecular sciences
|August 26, 2023
概括
这项研究研究了固氧燃料电池的LaNi0.6Fe0.4O3- (LNF) 阴极上的氧气交换机制. 研究人员确定了氧气交换的速度决定性步骤,这对于改善阴极性能至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 化学工程是化学工程的重要组成部分.
背景情况:
- LaNi0.6Fe0.4O3- (LNF) 是一种混合的离子电子氧化物,有可能作为固氧化物燃料电池 (SOFC) 的陶阴极.
- 在阴极表面有效的氧气交换动力学对于SOFC的性能和耐用性至关重要.
- 了解与LNF的氧相互作用机制对于优化其在SOFC中的应用至关重要.
研究的目的:
- 为了研究O2和LNF阴极材料之间的氧气交换机制.
- 在各种条件下确定动力参数,包括氧气交换速率和扩散系数.
- 为了确定LNF的氧气交换过程中的速度决定性步骤.
主要方法:
- 使用了两个同位素方法,与气相平衡的同位素交换 (IE-GPE) 和脉冲同位素交换 (PIE),与O标记的氧.
- 在广泛的温度范围 (350-800°C) 和氧气压力 (10-200 mbar) 上进行了实验.
- 应用数学模型来分析运动数据并计算氧气交换率 (r) 和扩散系数 (D).
主要成果:
- 计算的氧气交换率和扩散系数,这些系数取决于温度和氧气压力.
- 表面交换率 (0.73 ± 0.05 eV对于PIE,0.48 ± 0.02 eV对于IE-GPE) 和扩散系数 (0.62 ± 0.01 eV对于IE-GPE) 的确定激活能量.
- 密度和粉末LNF样本之间的交换和扩散机制观察到的差异,归因于微观结构变化. 证明了氧气压力对不同交换类型的贡献的影响.
结论:
- 首次确定了LNF材料的氧气交换过程中的速度决定性步骤.
- 这项研究提供了对LNF氧气交换和扩散的不同机制的见解,这些机制受样本形态和操作条件的影响.
- 这些发现对于合理设计和优化基于LNF的阴极以提高SOFC性能至关重要.
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