In Situ Studies of the Temperature-Dependent Surface Structure and Chemistry of Single-Crystalline (001)-Oriented La 0.8 Sr 0.2 CoO 3−δ Perovskite Thin Films

Zhenxing Feng, Ethan J. Crumlin, Wesley T. Hong, Dongkyu Lee, Eva Mutoro, Michael D. Biegalski, Hua Zhou, Hendrik Bluhm, Hans M. Christen, Yang Shao-Horn

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Perovskites are used to promote the kinetics of oxygen electrocatalysis in solid oxide fuel cells and oxygen permeation membranes. Little is known about the surface structure and chemistry of perovskites at high temperatures and partial oxygen pressures. Combining in situ X-ray reflectivity (XRR) and in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we report, for the first time, the evolution of the surface structure and chemistry of (001)-oriented perovskite La0.8Sr0.2CoO 3-δ (LSC113) and (La0.5Sr 0.5)2CoO4+δ (LSC214)-decorated LSC113 (LSC113/214) thin films as a function of temperature. Heating the (001)-oriented LSC113 surface leads to the formation of surface LSC214-like particles, which is further confirmed by ex situ Auger electron spectroscopy (AES). In contrast, the LSC113/214 surface, with activities much higher than that of LSC 113, is stable upon heating. Combined in situ XRR and APXPS measurements support that Sr enrichment may occur at the LSC113 and LSC214 interface, which can be responsible for its markedly enhanced activities. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)1512-1518
Number of pages7
JournalThe Journal of Physical Chemistry Letters
Volume4
Issue number9
DOIs
StatePublished - Apr 18 2013
Externally publishedYes

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