揭示单原子催化剂氧降解反应的潜在依赖速度决定步骤
Hui-Min Yan1, Gang Wang1, Xin-Mao Lv1
1Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
Journal of the American Chemical Society
|January 14, 2025
概括
这项研究揭示了单原子催化剂 (SAC) 氧降解反应 (ORR) 的速率决定性步骤随着应用潜力而变化,解决了长期的争论并指导了催化剂设计.
科学领域:
- 电化学
- 材料科学
- 计算化学
背景情况:
- 单原子催化剂 (SAC) 在氧降解反应 (ORR) 中有望替代.
- 了解SAC的反应机制和速率决定步骤对于优化至关重要,但仍然具有挑战性.
- 现有的模型通常假定RDS是不变的,这可能不反映现实的运行条件.
研究的目的:
- 在由配合的石墨烯 (Fe-N4/C) 支持的单个铁原子催化剂上研究ORR的潜在依赖性自由能量.
- 为了阐明ORR的真实速率决定步骤 (RDS) 在一个潜在的范围内.
- 揭示动态水吸附在SAC的ORR动力学中的作用.
主要方法:
- 最初的分子动力学模拟用于研究反应能量.
- 使用热力学整合方法来计算自由能景观.
- 微动力学建模与模拟数据相结合,分析反应途径并确定RDS.
主要成果:
- 在Fe-N4/C上的ORR的RDS被证明是潜在依赖的,而不是不变的.
- 在低电位时,水脱吸是RDS;在高电位时,它转移到质子化步骤 (*OH,O2*,O*).
- 水的动态吸附在促进部位释放和提高ORR率方面发挥着关键作用.
结论:
- 这项研究解决了ORR对SAC的RDS的争议.
- 它强调,外热度最低的阶段并不总是RDS.
- 在现实潜力下检查动力障碍对于理解和改进SAC电催化性能至关重要.
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