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H/D同位素效应揭示了用于氧化水的共基氧化物中控制催化活性的因素
Chiara Pasquini1, Ivelina Zaharieva1, Diego González-Flores1
1Department of Physics , Freie Universität Berlin , Arnimallee 14 , 14195 Berlin , Germany.
Journal of the American Chemical Society
|January 18, 2019
在PubMed 上查看摘要
概括
替代显著降低了氧化催化剂的水氧化催化,表明质子合电子转移不是决定速度的. 氧-氧键的形成被认为是关键步骤.
科学领域:
- 催化剂
- 电化学
- 人工光合作用
背景情况:
- 水的电化学氧化对于人工光合作用至关重要.
- 质子合电子转移 (PCET) 是水氧化机制的一个关键步骤.
- 了解PCET机制对于设计高效的催化剂至关重要.
研究的目的:
- 阐明基于Co的无形氧化物催化剂的电化学水氧化机制.
- 研究质子合电子转移在催化循环中的作用.
- 在水氧化过程中确定速度的步骤.
主要方法:
- 同位素替代研究 (替代,18O替代16O).
- 在现场和准在现场的X射线吸收光谱 (XAS).
- 时间解析的光谱电化学测量.
主要成果:
- 替代导致催化活性降低87%,而18O替代导致10%的降低.
- 同位素效应表明了氧化潜力的积极转变.
- 没有动态同位素效应表明电子转移不是决定速度的.
- 催化速率与平均氧化状态呈指数相关.
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