Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

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• 作者：Eva Mutoro ; Ethan J. Crumlin ; Hendrik P枚pke ; Bjoern Luerssen ; Matteo Amati ; Majid K. Abyaneh ; Michael D. Biegalski ; Hans M. Christen ; Luca Gregoratti ; J眉rgen Janek ; Yang Shao-Horn
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：January 5, 2012
• 年：2012
• 卷：3
• 期：1
• 页码：40-44
• 全文大小：365K
• 年卷期：v.3,no.1(January 5, 2012)
• ISSN：1948-7185

文摘

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 La_0.8Sr_0.2CoO3鈭捨?/sub> (LSC₁₁₃), (La_0.5Sr_0.5)₂CoO_4卤未 (LSC₂₁₄), and LSC₂₁₄-decorated LSC₁₁₃ films (LSC_113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC_113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites.

Keywords:

electrochemistry; epitaxial; fuel cells; in situ; perovskite; surface; XPS