Vinogradov Ilya, Singh Suryansh, Lyle Hanna, Paolino Michael, Mandal Aritra, Rossmeisl Jan, Cuk Tanja
Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, Boulder, CO, USA.
Materials Science and Engineering Program, University of Colorado, Boulder, Boulder, CO, USA.
Nat Mater. 2022 Jan;21(1):88-94. doi: 10.1038/s41563-021-01118-9. Epub 2021 Nov 1.
Theoretical descriptors differentiate the catalytic activity of materials for the oxygen evolution reaction by the strength of oxygen binding in the reactive intermediate created upon electron transfer. Recently, time-resolved spectroscopy of a photo-electrochemically driven oxygen evolution reaction followed the vibrational and optical spectra of this intermediate, denoted M-OH. However, these inherently kinetic experiments have not been connected to the relevant thermodynamic quantities. Here we discover that picosecond optical spectra of the Ti-OH population on lightly doped SrTiO are ordered by the surface hydroxylation. A Langmuir isotherm as a function of pH extracts an effective equilibrium constant relatable to the free energy difference of the first oxygen evolution reaction step. Thus, time-resolved spectroscopy of the catalytic surface reveals both kinetic and energetic information of elementary reaction steps, which provides a critical new connection between theory and experiment by which to tailor the pathway of water oxidation and other surface reactions.
理论描述符通过电子转移时形成的反应中间体中氧结合的强度来区分材料对析氧反应的催化活性。最近，光电化学驱动的析氧反应的时间分辨光谱跟踪了这个中间体（记为M-OH）的振动光谱和光学光谱。然而，这些本质上的动力学实验尚未与相关的热力学量联系起来。在这里，我们发现轻掺杂SrTiO上Ti-OH群体的皮秒光学光谱按表面羟基化顺序排列。作为pH函数的朗缪尔等温线提取了一个与析氧反应第一步的自由能差相关的有效平衡常数。因此，催化表面的时间分辨光谱揭示了基本反应步骤的动力学和能量信息，这在理论和实验之间提供了一个关键的新联系，据此可以定制水氧化和其他表面反应的途径。
