Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Energy Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
J Am Chem Soc. 2020 May 13;142(19):8748-8754. doi: 10.1021/jacs.0c01104. Epub 2020 Apr 29.
The origins of the pH-dependent kinetics of hydrogen evolution and oxidation reactions on Pt surfaces are unsolved dilemmas that have lasted for over half a century. In this study, surface-enhanced infrared absorption spectroscopy is applied to directly monitor the vibrational behaviors of adsorbed hydrogen atoms and interfacial water molecules on Pt surfaces in a wide pH window from 1.1 to 12.9. For the first time, we successfully measure the pH-dependent changes of hydrogen and water binding strength according to their vibrational wavenumbers, which are both monotonously weakened as the solution pH increases. Their changes are the net results of altered electrochemical interface environments and are important contributions to the pH-dependent hydrogen reaction kinetics. Our results add significant new insights into the role of interfacial environments on electrocatalysis.
Pt 表面上氢析出和氧化反应的 pH 依赖性动力学的起源是一个持续了半个多世纪的未解难题。在这项研究中，表面增强红外吸收光谱被应用于直接监测 Pt 表面上吸附氢原子和界面水分子在从 1.1 到 12.9 的宽 pH 窗口中的振动行为。首次根据其振动波数成功测量了氢和水结合强度随 pH 的变化，这两者都随着溶液 pH 的增加而单调减弱。它们的变化是电化学界面环境改变的净结果，对 pH 依赖性氢反应动力学有重要贡献。我们的结果为界面环境在电催化中的作用提供了新的重要见解。
