The development of inexpensive, earth abundant, and bioinspired oxygen evolution electrocatalysts that are easily accessible and scalable is a principal requirement with regard to the feasibility of water splitting for large‐scale chemical energy storage. A unique, versatile, and scalable approach has been developed to fabricate manganese oxide films from single layers to multilayers with a controlled thickness and high reproducibility. The produced MnO_x films are composed of small nanostructures that are assembled closely in the form of porous sponge‐like layers. The films were investigated for the electrochemical oxygen evolution reaction in alkaline media and demonstrate a remarkable activity as well as a superior stability of over 60 h. To elucidate the catalytically active species, as well as the striking structural characteristics, the films were further examined in depth by using SEM, TEM, and X‐ray photoelectron spectroscopy, as well as quasi in situ extended X‐ray absorption fine structure and X‐ray absorption near edge structure analysis. The MnO_x catalyst films excel because of a favorably high fraction of Mn³⁺ ions that are retained even after operation at oxidizing potentials. Upon exposure to oxidizing potentials in strongly alkaline aqueous electrolyte, the catalyst material maintains its structural integrity at the nanostructural, morphological, and atomic level.

中文翻译：

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纳米结构的氧化锰薄膜的简便形成作为高性能的氧析出催化剂

对于大规模化学能存储进行水分解的可行性，开发一种易于获取且可扩展的廉价，地球资源丰富且具有生物启发性的析氧电催化剂是一项主要要求。已经开发出一种独特的，通用的和可扩展的方法来制造具有受控厚度和高再现性的从单层到多层的氧化锰膜。产生的MnO _x薄膜由小的纳米结构组成，这些纳米结构以多孔海绵状层的形式紧密组装。研究了该膜在碱性介质中的电化学氧释放反应，证明了其卓越的活性以及超过60小时的出色稳定性。为了阐明催化活性物种以及引人注目的结构特征，使用SEM，TEM和X射线光电子能谱以及准原位扩展X射线吸收精细结构和X对薄膜进行了更深入的检查。边缘结构分析的射线吸收。MnO _x催化剂薄膜之所以出色，是因为Mn ^3+的比例很高甚至在氧化电势下仍保留的离子。在强碱性水性电解质中暴露于氧化电势后，催化剂材料在纳米结构，形态和原子水平上保持其结构完整性。