Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials
Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials
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DOI：
10.1021/jz201523y
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发表时间：
2012-01-05
影响因子：
5.7
通讯作者：
Shao-Horn, Yang
中科院分区：
文献类型：
--
作者：
Mutoro, Eva;Crumlin, Ethan J.;Shao-Horn, Yang
钙钛矿氧化物可以表现出多种有趣的特性，例如催化活性和电子/离子导电性，因此它们已被用于许多固态设备，例如固体氧化物燃料电池（SOFC）和传感器。由于钙钛矿的表面成分可以极大地影响催化性能，因此了解和控制其表面成分对于提高器件性能至关重要。在这项研究中，我们证明了通过施加小的电势偏置，可以在高温下可逆地控制钙钛矿基薄膜的表面锶（Sr）和钴（Co）浓度。利用基于同步加速器的 X 射线光电子能谱 (XPS) 原位研究了 La0.8Sr0.2、CoO3-delta(LSC113)、(La0.5Sr0.5)(2)CoO4 +/-delta (LSC214) 和 LSC214 修饰的 LSC113 薄膜 (LSC113/214) 的表面成分变化， 其中 LSC113/214 表面的表面 Sr 变化最大。这些发现提供了可逆控制钙钛矿表面功能的潜力。
Perovskite oxides can exhibit a wide range of interesting characteristics such as being catalytically active and electronically/ionically conducting, and thus, they have been used in a number of solid-state devices such as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions of perovskites can greatly influence the catalytic properties, knowing and controlling their surface compositions is crucial to enhance device performance. In this study, we demonstrate that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La0.8Sr0.2,CoO3-delta(LSC113), (La0.5Sr0.5)(2)CoO4 +/-delta (LSC214), and LSC214-decorated LSC113 films (LSC113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites.