Anomalous Interface and Surface Strontium Segregation in (La 1– y Sr y ) 2 CoO 4±δ /La 1– x Sr x CoO 3−δ Heterostructured Thin Films

Zhenxing Feng, Yizhak Yacoby, Milind J. Gadre, Yueh-Lin Lee, Wesley T. Hong, Hua Zhou, Michael D. Biegalski, Hans M. Christen, Stuart B. Adler, Dane Morgan, Yang Shao-Horn

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Heterostructured oxides have shown unusual electrochemical properties including enhanced catalytic activity, ion transport, and stability. In particular, it has been shown recently that the activity of oxygen electrocatalysis on the Ruddlesden-Popper/perovskite (La1-ySr y)2CoO4±δ/La1-xSr xCoO3-δ heterostructure is remarkably enhanced relative to the Ruddlesden-Popper and perovskite constituents. Here we report the first atomic-scale structure and composition of (La1-ySr y)2CoO4±δ/La1-xSr xCoO3-δ grown on SrTiO3. We observe anomalous strontium segregation from the perovskite to the interface and the Ruddlesden-Popper phase using direct X-ray methods as well as with ab initio calculations. Such Sr segregation occurred during the film growth, and no significant changes were found upon subsequent annealing in O2. Our findings provide insights into the design of highly active catalysts for oxygen electrocatalysis. © 2014 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)1027-1034
Number of pages8
JournalThe Journal of Physical Chemistry Letters
Volume5
Issue number6
DOIs
StatePublished - Mar 7 2014
Externally publishedYes

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