表面的水方向决定了的演化反应动力学
Aamir Hassan Shah1, Zisheng Zhang1, Chengzhang Wan1,2
1Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
Journal of the American Chemical Society
|March 27, 2024
概括
的演变反应 (HER) 动力学取决于pH值. 较高的pH通过改变界面水的方向,削弱O-H键,并改变反应路径来加速HER.
科学领域:
- 电化学
- 表面科学
- 催化剂
背景情况:
- 在性介质中的 (Pt) 表面上的演化反应 (HER) 的动力学尚未完全理解.
- 了解pH依赖的HER动力学对于高效的电化学过程至关重要.
研究的目的:
- 在性条件下研究表面的PH依赖HER动态的分子水平机制.
- 阐明界面水和表面吸附剂在HER性能中的作用.
主要方法:
- 组合循环电量测量 (CV) 和电传输光谱 (ETS) 来探测Pt表面.
- 在各种pH值 (pH7-13) 上进行了实验.
- 使用固定电位计算和化学结合分析.
主要成果:
- 观察到HER Tafel斜率从~110 mV/十年 (pH 7-10) 到~53 mV/十年 (pH 11-13) 的显著变化,表明pH更高时的动力学加速.
- ETS研究显示,导电率在pH10附近的pH依赖转换与表面吸附物的变化相关.
- 计算表明水界的方向从O-向下转变为H-向下超过pH10.
结论:
- 在较高的pH值下加速的HER动力学归因于界面水分子的重定向.
- 这种重定位削弱了OH键,改变了反应途径,并提高了HER的性能.
- 提供了性介质中依赖pH的HER动态的分子层面的理解.
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