In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts
In Situ XANES/XPS Investigation of Doped Manganese Perovskite Catalysts
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DOI：
10.3390/catal4020129
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发表时间：
2014-06-01
期刊：
影响因子：
3.9
通讯作者：
Jooss, Christian
中科院分区：
文献类型：
--
作者：
Mierwaldt, Daniel;Mildner, Stephanie;Jooss, Christian
原位研究催化剂对于了解其表面结构和运行中的电子状态具有重要意义。在此，我们提出了一个研究的外延锰氧化物钙钛矿薄膜（Pr 1-xCaxMnO 3）活性的析氧反应（OER）从电催化水裂解。在超高真空和水蒸气中，在室温下，在正偏压下，对Mn的L-和O-K-边进行了X射线吸收近边谱（XANES），并对O-1 s和Ca-2 p态进行了X射线光电子能谱（XPS）.结果表明，在OER的氧化条件下，在催化剂表面产生还原的Mn 2+物种。Mn的价态移动伴随着表面氧空位的形成。催化剂在O-2气氛中在120 ℃下退火恢复原始表面。
Studying catalysts in situ is of high interest for understanding their surface structure and electronic states in operation. Herein, we present a study of epitaxial manganite perovskite thin films (Pr1-xCaxMnO3) active for the oxygen evolution reaction (OER) from electro-catalytic water splitting. X-ray absorption near-edge spectroscopy (XANES) at the Mn L- and O K-edges, as well as X-ray photoemission spectroscopy (XPS) of the O 1s and Ca 2p states have been performed in ultra-high vacuum and in water vapor under positive applied bias at room temperature. It is shown that under the oxidizing conditions of the OER a reduced Mn2+ species is generated at the catalyst surface. The Mn valence shift is accompanied by the formation of surface oxygen vacancies. Annealing of the catalysts in O-2 atmosphere at 120 degrees C restores the virgin surfaces.