Hetero-structured interfaces of oxides, which can exhibit reactivity characteristics remarkably different from bulk oxides, are interesting systems to explore in search of highly active fuel cell catalysts for oxygen electrocatalysis. (001)-oriented La0.6Sr0.4CoO 3-δ (LSC60-40113) thin films having thicknesses from tens to hundreds of nanometers were grown epitaxially on (001)-oriented yttria-stabilized zirconia (YSZ). Atomic force microscopy showed that all the film surfaces were of high quality with average surface roughness approximately one nanometer. The surface oxygen exchange kinetics of these films were determined by electrochemical impedance spectroscopy. While (001)-oriented LSC60-40113 thin films were found to have similar surface oxygen exchange coefficients to LSC60-40113 bulk, surface coverage of (001)-oriented (La0.5Sr0.5)2CoO4±δ (LSC214) on the LSC60-40113 thin films led to significant enhancement in the surface oxygen kinetics up to ∼3 orders of magnitude. Interestingly, LSC214-decorated LSC60-40113 films have comparable surface exchange kinetics (∼1 · 10 cm·s -1 at 550°C) to similarly prepared LSC214-decorated La0.8Sr0.2CoO3-δ films. Such high surface oxygen kinetics are among the most active SOFC cathode materials reported to date. © 2012 The Electrochemical Society.
|Original language||English (US)|
|Number of pages||1|
|Journal||JOURNAL OF THE ELECTROCHEMICAL SOCIETY|
|State||Published - 2012|
Bibliographical noteKAUST Repository Item: Exported on 2021-09-16
Acknowledgements: This work was supported in part by DOE (SISGR DE-SC0002633), King Abdullah University of Science and Technology, and King Fahd University of Petroleum and Minerals in Dharam, Saudi Arabia, for funding the research reported in this paper through the Center for Clean Water and Clean Energy at MIT and KFUPM. The PLD preparation performed was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific user Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. E. Mutoro is grateful for financial support from the German Research Foundation (DFG research scholarship). The authors thank Prof. Harry Tuller and Dr. Gerardo Jose la O' for their fruitfully discussion.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.