Heterostructured interfaces of oxides, which can exhibit transport and reactivity characteristics remarkably different from those of bulk oxides, are interesting systems to explore in search of highly active cathodes for the oxygen reduction reaction (ORR). Here, we show that the ORR of ∼85 nm thick La0.8Sr0.2CoO3-δ (LSC113) films prepared by pulsed laser deposition on (001)-oriented yttria-stabilized zirconia (YSZ) substrates is dramatically enhanced (∼3-4 orders of magnitude above bulk LSC113) by surface decorations of (La 0.5Sr0.5)2CoO4±δ (LSC214) with coverage in the range from ∼0.1 to ∼15 nm. Their surface and atomic structures were characterized by atomic force, scanning electron, and scanning transmission electron microscopy, and the ORR kinetics were determined by electrochemical impedance spectroscopy. Although the mechanism for ORR enhancement is not yet fully understood, our results to date show that the observed ORR enhancement can be attributed to highly active interfacial LSC113/LSC214 regions, which were shown to be atomically sharp. © 2010 American Chemical Society.
|Original language||English (US)|
|Number of pages||7|
|Journal||The Journal of Physical Chemistry Letters|
|State||Published - Oct 15 2010|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported in part by the NSF (CBET 08-44526), DOE (SISGR DE-SC0002633), and King Abdullah University of Science and Technology. E.M. is grateful for financial support from the German Research Foundation (research scholarship). The portion of research performed at the Center for Nanophase Materials Sciences as well as FIB instrument access via ORNL’s ShaRE user facility was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE. The STEM work was sponsored by the Materials Sciences and Engineering Division, Office of Basic Energy Sciences of the U.S. DOE.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.