氧化物诱导的Fe-N-C催化剂过氧化:对ORR活动的影响
Ankita Morankar1, Plamen Atanassov2, Jeffrey Greeley1
1Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA.
概括
过氧化通过氧化附近的碳原子来降解铁--碳 (Fe-N-C) 电催化剂. 这种氧化减少了催化活性,并导致不可逆转的碳腐蚀,阻碍了燃料电池的性能.
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
- 计算化学计算化学
背景情况:
- 铁--碳 (Fe-N-C) 电催化剂是用于氧降解反应 (ORR) 的贵金属的经济有效替代品.
- 有限的稳定性,特别是由于氧化降解,阻碍了Fe-N-C催化剂在燃料电池中的广泛应用.
研究的目的:
- 调查Fe-N-C电催化剂的降解机制,由过氧化 (H2O2) 引起,这是ORR的副产品.
- 阐明Fe-N-C活性位点上H2O2激活的热力学和动力学途径.
主要方法:
- 用周期密度函数理论 (DFT) 的计算来研究电子结构和能量学.
- 使用ab-initio分子动力学 (AIMD) 模拟来探测反应动力学和动态过程.
主要成果:
- 邻近FeN4活性位点的碳原子经历了显著的过氧化,形成基和环氧基.
- 这些氧化物种与ORR中间体相互作用,降低了整体催化活性.
- 过氧化部位的形成被认为是不可逆转的碳腐蚀和催化剂失活的前体.
结论:
- 过氧化在Fe-N-C电催化剂的降解中起着至关重要的作用.
- 了解和减轻H2O2诱导的氧化对于提高燃料电池应用的Fe-N-C催化剂的耐用性至关重要.
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