Zhuang Yong-Bin, Pasquarello Alfredo
Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland.
Angew Chem Int Ed Engl. 2025 Aug 4;64(32):e202507071. doi: 10.1002/anie.202507071. Epub 2025 May 24.
The oxygen evolution reaction (OER) at the -water interface is considered to be the bottleneck of the overall water splitting at this aqueous interface. To provide insight into the mechanism of this reaction, the focus is set on the first proton-coupled electron transfer (PCET). The free-energy surface of this first step is obtained by combining on-the-fly probability-enhanced sampling and machine learning potentials at the hybrid functional level of accuracy. Our study reveals that proton transfer precedes electron transfer and determines the reaction barrier, consistent with kinetic-isotope-effect experiments. The calculated reaction barrier amounts to eV. The proton moves from the adsorbed water molecule to a surface O atom through a direct transfer mechanism. The hole hopping to the resulting hydroxide occurs via the mediation of a surface Bi atom. The presented framework can be generally applied to other PCET steps and other oxides, thus opening the door to a comprehensive investigation of the OER mechanism at oxide-water interfaces.
在水界面处的析氧反应（OER）被认为是该水相界面处整体水分解的瓶颈。为了深入了解该反应的机制，重点聚焦于首个质子耦合电子转移（PCET）。通过在混合泛函精度水平上结合实时概率增强采样和机器学习势能，获得了这第一步的自由能表面。我们的研究表明，质子转移先于电子转移并决定反应势垒，这与动力学同位素效应实验一致。计算得到的反应势垒为 电子伏特。质子通过直接转移机制从吸附的水分子转移到表面 O 原子。空穴通过表面 Bi 原子的介导跳跃到生成的氢氧化物上。所提出的框架可普遍应用于其他 PCET 步骤和其他氧化物，从而为全面研究氧化物 - 水界面处的 OER 机制打开了大门。
