在高性能无PGMOR催化剂的活性部位的直接原子层面洞察
Hoon T Chung1, David A Cullen2, Drew Higgins1
1Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
概括
类无金属催化剂为燃料电池提供了更便宜的替代品. 这项研究表明,铁碳催化剂的性能与气燃料电池的性能相当.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 类无金属 (无PGM) 催化剂对于降低聚合物电解质燃料电池 (PEFC) 的成本至关重要.
- 关键的挑战包括确定氧减少反应 (ORR) 的活性点,并在汽车条件下实现气燃料电池的竞争性性能.
研究的目的:
- 通过使用铁碳催化剂来证明气燃料电池的性能提高.
- 识别和可视化负责氧降解反应的催化活性位点.
主要方法:
- 使用两个前体的铁--碳催化剂的合成,从而产生层次性的多孔性.
- 在-空气燃料电池的性能评估中,将电流密度与阴极进行比较.
- 使用偏差校正扫描传导电子显微镜直接可视化拟议的催化活性部位 (FeN4).
- 活动地点的计算探索及其与碳结构的关系.
主要成果:
- 合成的铁碳催化剂在动力区域 (电压>0.75V) 的负荷为0.1 mg Pt/cm2时表现出与阴极相当的性能.
- 直接可视化了碳嵌入协调铁 (FeN4) 的活性部位.
- 计算分析提供了与活跃地点相关的特定碳结构的作用.
结论:
- 具有层次孔隙性的铁碳催化剂可以在PEFC中实现竞争性性能,与基催化剂相竞争.
- 直接可视化和计算分析证实FeN4位点是氧减少反应的关键活性成分.
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