从光电化学水氧化过程中确定H2O2演变的动力学
Dongfeng Li1,2, Ruifang Wei1,3, Deyun Zhang1,2
1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian, China.
Nature communications
|August 23, 2025
概括
通过二碳酸盐离子 (HCO3-) 增强光电化学水氧化以产生过氧化 (H2O2). 这项研究揭示了二氧化碳通过优化反应动力学来加速H2O2的产生,
科学领域:
- 电化学
- 光催化
- 化学动力学
背景情况:
- 光电化学 (PEC) 水氧化是一种生产过氧化 (H2O2) 的可持续方法.
- PEC水氧化的效率受到电解质组成,特别是二碳酸离子 (HCO3-) 的显著影响.
- 在PEC水氧化过程中控制H2O2演变的精确动力机制尚不清楚.
研究的目的:
- 在PEC水氧化中阐明H2O2演变的电荷动态和反应动力学.
- 研究二碳酸在促进H2O2生成中的作用.
- 建立一种控制催化反应选择性的机制.
主要方法:
- 使用时间解析的光谱技术来探测电荷动态.
- 进行速度定律分析以确定反应动力学.
- 使用和不使用二碳酸离子的H2O2演化反应速率和周转频率的比较.
主要成果:
- H2O2进化与O2进化具有相同的第一孔转移动态.
- H2O2进化反应遵循一阶动力学,速度决定的步骤是二电子水氧化路径中的第一孔中间体的消耗.
- 与4电子水氧化路径相比,二碳酸离子在速率常数上加快了这些中间体的消耗约30倍,在循环频率上加快了60倍.
结论:
- 通过2电子水氧化生产H2O2的速度决定的步骤是初始孔中间体的消耗.
- 双碳酸盐离子显著增强H2O2的演变,通过动态偏好2电子通路而不是4电子通路.
- 这项研究提供了通过动态调制控制催化反应选择性的见解.
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