Sarabia Francisco, Gomez Rodellar Carlos, Roldan Cuenya Beatriz, Oener Sebastian Z
Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, Berlin, Germany.
Nat Commun. 2024 Sep 18;15(1):8204. doi: 10.1038/s41467-024-52499-9.
The interface between electrocatalyst and electrolyte is highly dynamic. Even in absence of major structural changes, the intermediate coverage and interfacial solvent are bias and time dependent. This is not accounted for in current kinetic models. Here, we study the kinetics of the hydrogen evolution, ammonia oxidation and oxygen reduction reactions on polycrystalline Pt with distinct intrinsic rates and intermediates (e.g. *H, *OH, *NH, *N). Despite these differences, we discover shared relationships between the pre-exponential factor and the activation energy that we link to solvation kinetics in the presence of electronic excess charge and charged intermediates. Further, we study dynamic changes of these kinetic parameters with a millisecond time resolution during electrosorption and double layer charging and dynamic *N and *NO poisoning. Finally, we discover a pH-dependent activation entropy that explains non-Nernstian overpotential shifts with pH. In sum, our results demonstrate the importance of accounting for a bias and time-dependent interfacial solvent and catalyst surface.
电催化剂与电解质之间的界面具有高度动态性。即使在没有重大结构变化的情况下，中间体覆盖度和界面溶剂也会随偏压和时间而变化。当前的动力学模型并未考虑到这一点。在此，我们研究了在具有不同本征速率和中间体（例如*H、*OH、NH、N）的多晶Pt上析氢、氨氧化和氧还原反应的动力学。尽管存在这些差异，但我们发现了指前因子与活化能之间的共同关系，我们将其与存在电子过量电荷和带电中间体时的溶剂化动力学联系起来。此外，我们在电吸附、双层充电以及动态N和NO中毒过程中，以毫秒级时间分辨率研究了这些动力学参数的动态变化。最后，我们发现了一个pH依赖的活化熵，它解释了非能斯特过电位随pH的变化。总之，我们的结果证明了考虑偏压和时间依赖的界面溶剂及催化剂表面的重要性。
