Dynamically Stable Active Sites from Surface Evolution of Perovskite Materials during the Oxygen Evolution Reaction
Dynamically Stable Active Sites from Surface Evolution of Perovskite Materials during the Oxygen Evolution Reaction
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DOI：
10.1021/jacs.0c08959
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发表时间：
2021-01-05
影响因子：
15
通讯作者：
Markovic, Nenad M.
中科院分区：
文献类型：
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作者：
Lopes, Pietro P.;Chung, Dong Young;Markovic, Nenad M.
钙钛矿型氧化物是碱性介质中一类重要的析氧反应催化剂，尽管其活性中心难以捉摸。在这里，我们证明了La(1-x)SrxCoO(3)模型钙钛矿中OER活性的来源是氢化钴(氧)氧化物(CoOxHy)的薄表面层，它与存在于电解液中的痕量铁物种相互作用，产生动态稳定的活性中心。氢氧化物氧化层的产生是由A位溶解和O空位产生驱动的表面演化过程的结果。反过来，与纳米级钴氢(氧)氧化物簇合物相比，这使CoOxHy/LSCO的抗Co溶解稳定性提高了10倍，活性稳定因子增加了3倍。我们的结果为活性和稳定的钙钛矿型氧化物OER材料提供了新的设计规则。
Perovskite oxides are an important class of oxygen evolution reaction (OER) catalysts in alkaline media, despite the elusive nature of their active sites. Here, we demonstrate that the origin of the OER activity in a La(1-x)SrxCoO(3) model perovskite arises from a thin surface layer of Co hydr(oxy)oxide (CoOxHy) that interacts with trace-level Fe species present in the electrolyte, creating dynamically stable active sites. Generation of the hydr(oxy)oxide layer is a consequence of a surface evolution process driven by the A-site dissolution and O-vacancy creation. In turn, this imparts a 10-fold improvement in stability against Co dissolution and a 3-fold increase in the activity-stability factor for CoOxHy/ LSCO when compared to nanoscale Co-hydr(oxy)oxides clusters. Our results suggest new design rules for active and stable perovskite oxide-based OER materials.