性介质中的氧降解反应导致Fe-N-C电催化剂的铁液
Yu-Ping Ku1,2, Konrad Ehelebe1,2, Andreas Hutzler1
1Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Forschungszentrum Jülich GmbH, Cauerstraße 1, 91058 Erlangen, Germany.
Journal of the American Chemical Society
|May 24, 2022
概括
铁--碳 (Fe-N-C) 电催化剂对燃料电池 (FC) 是有前途的. 这项研究揭示了氧降解反应 (ORR) 活性与铁溶解之间的直接联系,引入了新的稳定性指标.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 铁--碳 (Fe-N-C) 电催化剂在燃料电池 (FC) 的性介质中表现出类似的活性.
- 证明高耐用性和寿命对于广泛的FC应用至关重要.
- 在操作条件下对降解途径的有限理解阻碍了稳定的Fe-N-C催化剂的开发.
研究的目的:
- 在燃料电池相关条件下研究Fe-N-C电催化剂的铁 (Fe) 溶解.
- 确定电化学活动和Fe降解之间的定量关系.
- 引入一种用于评估电催化剂稳定性的新指标.
主要方法:
- 使用气体扩散电极半细胞与感应合等离子体质谱 (ICP-MS).
- 在模仿FC环境的条件下运行,包括多孔催化剂层 (CL) 和高电流密度 (-125 mA·cm-2).
- 改变氧降解反应 (ORR) 速率以研究其对Fe溶解的影响.
主要成果:
- 在传递的法拉第总电荷和溶解的Fe量之间观察到线性相关性.
- 这种相关性表明ORR和Fe溶解之间存在机械联系,可能是通过Fe氧化还原转换中的常见中间体.
- 一个新的稳定度指标,S数,是基于这种线性关系而开发的.
结论:
- 在Fe-N-C电催化剂中的Fe溶解与ORR过程中传递的电荷成正比.
- 电催化剂的S数为快速稳定性选提供了一个简单而强大的工具.
- 这项工作增强了对催化剂层Fe-N-C降解的机制理解,促进了更耐用的催化剂的设计.
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