Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

Eva Mutoro, Ethan J. Crumlin, Hendrik Pöpke, Bjoern Luerssen, Matteo Amati, Majid K. Abyaneh, Michael D. Biegalski, Hans M. Christen, Luca Gregoratti, Jürgen Janek, Yang Shao-Horn

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

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 0.2CoO 3-δ (LSC 113), (La 0.5Sr 0.5) 2CoO 4±δ (LSC 214), and LSC 214-decorated LSC 113 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. © 2011 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)40-44
Number of pages5
JournalThe Journal of Physical Chemistry Letters
Volume3
Issue number1
DOIs
StatePublished - Dec 13 2011
Externally publishedYes

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