Real time in-situ microscopy imaging of surface structure and atom dynamics of heterogeneous catalysts is an important step for understanding reaction mechanisms. Here, using in-situ environmental transmission electron microscopy (ETEM), we directly visualize surface atom dynamics at manganite perovskite catalyst surfaces for oxygen evolution reaction (OER), which are ≥20 times faster in water than in other ambients. Comparing (001) surfaces of La_0.6Sr_0.4MnO₃ and Pr_0.67Ca_0.33MnO₃ with similar initial manganese valence state and OER activity, but very different OER stability, allows us to distinguish between reversible surface adatom dynamics and irreversible surface defect chemical reactions. We observe enhanced reversible manganese adatom dynamics due to partial solvation in adsorbed water for the highly active and stable La_0.6Sr_0.4MnO₃ system, suggesting that aspects of homogeneous catalysis must be included for understanding the OER mechanism in heterogeneous catalysis.

多相催化剂的表面结构和原子动力学的实时原位显微镜成像是了解反应机理的重要步骤。在这里，使用原位环境透射电子显微镜（ETEM），我们可以直接观察到锰钙钛矿催化剂表面上用于氧释放反应（OER）的表面原子动力学，它在水中的速度比其他环境快20倍以上。La _0.6 Sr _0.4 MnO ₃和Pr _0.67 Ca _0.33 MnO _3的（001）表面比较具有相似的初始锰价态和OER活性，但OER稳定性却大不相同，这使我们能够区分可逆的表面原子动力学和不可逆的表面缺陷化学反应。对于高活性和稳定的La _0.6 Sr _0.4 MnO ₃体系，我们观察到由于吸附水中的部分溶剂化而增强了可逆锰吸附原子的动力学，这表明均相催化方面必须包括在内，以了解多相催化中的OER机理。