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.
Original language | English |
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Pages (from-to) | 1027-1034 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry Letters |
Volume | 5 |
Issue number | 6 |
DOIs | |
State | Published - 20 Mar 2014 |
Keywords
- ab initio calculation
- coherent Bragg rod analysis
- fuel cell
- heterostructure perovskites
- oxides
- strontium segregation
- surface and interface