在Fe-N-C催化剂上,氧降解反应的速度限制步骤是什么?
Saerom Yu1, Zachary Levell1, Zhou Jiang1
1Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States.
Journal of the American Chemical Society
|November 13, 2023
概括
铁碳催化剂的氧减速限制步骤是氧取代水,而不是化. 这一关键步骤
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 氧降解反应 (ORR) 对可再生能源技术至关重要.
- 用添加的石墨烯 (Fe-N-C) 中的单个铁原子是有前途的ORR催化剂.
- 在Fe-N-C的ORR中限制速度的步骤仍然未确定,阻碍了催化剂的改进.
研究的目的:
- 为了确定Fe-N-C催化剂的ORR的速度限制步骤.
- 阐明每个步骤的基本机制和激活能量.
- 为优化Fe-N-C催化剂性能提供见解.
主要方法:
- 首先使用了分子动力学模拟.
- 在恒定电极电位下进行模拟.
- 计算了所有反应步骤的激活能量.
主要成果:
- 速度限制步骤被确定为O2取代Fe位点上的吸附H2O.
- 这是通过协同脱吸-吸附机制发生的.
- 与预期相反,激活屏障随着电极电位的下降而降低.
结论:
- 这项研究挑战了普遍认为化限制了Fe-N-C的ORR率.
- 通过改变Fe-O2和Fe-H2O结合能量来解释潜在依赖的动力学.
- 动力学研究对于推进异质电催化研究至关重要.
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