化学
析氧
钙钛矿(结构)
活性氧
氧气
化学物理
作者
Pietro P. Lopes,Dong Young Chung,Xue Rui,Hong Zheng,Haiying He,Pedro Farinazzo Bergamo Dias Martins,Dusan Strmcnik,Vojislav R. Stamenkovic,Peter Zapol,John F. Mitchell,Robert F. Klie,Nenad M. Markovic
摘要
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 La1-xSrxCoO3 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.
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