Exploring high-performance electrocatalysts for the oxygen evolution reaction (OER) is pivotal for renewable energy storage and conversion. The surface self-reconstruction during the OER is considered as the key of highly active catalysts, whereas identifying the local electronic and geometric structure of the reconstruction-derived components is challenging. Herein, an in situ exsolution method towards the typical LaCo_0.8Fe_0.2O_3−δ perovskite is developed to obtain a new type of lanthana-anchored CoFe catalyst. The optimized catalyst exhibits a low overpotential of 293 mV to reach the current density of 10 mA cm⁻² in 0.1 M KOH. Most importantly, operando X-ray absorption spectroscopy (XAS) measurements demonstrate that the CoFe species in the catalyst are nearly transformed into unique (Co/Fe)O(OH) with a definite coordination-unsaturated structure under electrochemical conditions, which actually contributes to this superior performance. Moreover, the presence of the lanthana support promotes this transformation. Our work not only suggests a facile reconstructive strategy to dramatically enhance the OER activity of perovskite oxides in alkaline media, but also unravels the fine structure of true active sites through operando X-ray spectroscopic tracking.

中文翻译：

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Operando X射线光谱对锚定纳米颗粒的自我重建的追踪，作为对氧气逸出的高性能电催化剂†

探索用于氧气释放反应（OER）的高性能电催化剂对于可再生能源的存储和转化至关重要。OER过程中的表面自我重建被认为是高活性催化剂的关键，而如何识别源自重建的组分的局部电子和几何结构却具有挑战性。在本文中，在原位朝向典型LACO出溶方法_0.8铁_0.2 ø _{3- δ}的钙钛矿被显影以获得新型氧化镧-锚定的CoFe催化剂。优化的催化剂表现出293 mV的低过电势，以在0.1 M KOH中达到10 mA cm ^-2的电流密度。最重要的是，操作X射线吸收光谱（XAS）测量表明，在电化学条件下，催化剂中的CoFe物质几乎转化为具有确定的配位不饱和结构的独特（Co / Fe）O（OH），实际上有助于实现这一优异性能。此外，lanthana支持的存在促进了这种转变。我们的工作不仅意味着一个浅显的重建策略，极大地提高在碱性介质中钙钛矿氧化物的OER活动，同时也揭开了通过真正的活性位点的精细结构operando X射线光谱跟踪。