通过普遍的氧化吸附依赖的点行为揭示了电催化作用的动态pH的电双层起源
Lixin Su1, Junxiang Chen2, Fulin Yang1
1Hubei Key Laboratory of Electrochemical Power Sources, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Journal of the American Chemical Society
|May 23, 2023
概括
电催化中的动态pH效应显示出一个意想不到的转折点,而不是简单的pH下降. 这一发现揭示了电双层在氧化和演化反应 (HOR/HER) 中的关键作用.
科学领域:
- 电化学
- 催化剂
- 物理化学
背景情况:
- 动态pH效应,酸性和性电解质之间的电催化 (HOR/HER) 显著差距,阻碍了能的进步.
- 目前对这种效应的理解是不完整的,限制了性系统的催化剂开发.
研究的目的:
- 对贵重金属催化剂在广泛的pH范围 (1-13) 中的HOR/HER动力学的pH依赖性进行研究.
- 阐明驱动动力学pH效应的基本机制,并确定影响催化剂性能的关键因素.
主要方法:
- 在pH1至13的电解质中对贵金属电催化剂的HOR/HER动力学进行实验评估.
- 开发和应用三路微动力模型,将,水和吸附氧化物作为捐赠物.
- 催化剂氧化物结合能量的分析及其与动态行为的相关性.
主要成果:
- 在HOR/HER动力学的pH依赖性中观察到普遍的拐点行为,与预期的单调下降相反.
- 转折点的pH值和酸活性间隔被发现取决于催化剂的结能.
- 吸附氧化物 (OHad) 的形成被确定为HOR/HER动态的促进者,主要是通过增强电双层 (EDL) 键网络.
结论:
- 接口电双层 (EDL) 在电催化过程中观察到的动态pH效应中起着主导作用.
- 通过OHad形成改善EDL的键网络是增强HOR/HER动力学的关键机制,而不仅仅是改变表面反应能量.
- 这项研究为设计用于能源技术的先进电催化剂提供了关键的见解.
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