nomalous Interface and Surface Strontium Segregation in (La_1-ySr_y)₂CoO₄ /La_1-xSr_xCoO_3- Heterostructured Thin Films

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/jz500293d· OSTI ID:1131515

Feng, Zhenxing ^[1]; Yacoby, Yuzhak ^[1]; Gadre, Milind ^[1]; Lee, Yueh-Lin ^[1]; Hong, W. ^[2]; Zhou, Hua ^[3]; Biegalski, Michael D ^[4]; Christen, Hans M ^[4]; Adler, Stuart ^[5]; Morgan, Dane ^[6]; Shao-Horn, Yang ^[1]

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1. Massachusetts Institute of Technology (MIT)
2. Harvard University
3. Argonne National Laboratory (ANL)
4. ORNL
5. University of Washington
6. University of Wisconsin, Madison

Heterostructured materials have shown unusual physiochemical properties at the interfaces such as two dimensional electron gas systems, high-temperature superconductivity, and enhanced catalysis. Here we report the first atomic-scale evidence of the microscopic structure of a perovskite/Ruddlesden-Popper heterostructure (having La1-xSrxCoO3- /(La1-ySry)2CoO4 ), and anomalous strontium segregation at the interface and in the Ruddlesden-Popper structure using direct X-ray methods combined with ab initio calculations. The remarkably enhanced activity of such heterostructured surfaces relative to bulk perovskite and Ruddlesden-Popper oxides previously shown for oxygen electrocatalysis at elevated temperatures can be attributed to reduced thermodynamic penalty of oxygen vacancies in the oxide structure associated with Sr segregation observed in the heterostructure. Our findings provide insights for the design of highly active catalysts for energy conversion and storage applications.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1131515
• Journal Information: Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Journal Issue: 6 Vol. 5; ISSN 1948-7185
• Country of Publication: United States
• Language: English