Abstract
The effect due to systematic substitution of cobalt by iron in La0.6Ca0.4CoO3 perovskites on the oxygen evolution reaction (OER) in alkaline media has been investigated. These compounds were synthesized by a facile glycine-nitrate synthesis and the phase formation was confirmed by X-ray and neutron powder diffraction analysis. The apparent OER activity was evaluated by quasisteady state current measurements in alkaline media using a traditional three-electrode system. X-ray photoelectron spectroscopy shows an increase in Fe substitution causes an increase in the surface concentration of various Co oxidation states. A Tafel slope in the vicinity of 60 mV/decade and electrochemical reaction order for OH- near unity were found for the unsubstituted compounds. A decrease in the Tafel slope to 49 mV/decade was observed when iron is incorporated in high amounts in the perovskite structure. The area specific current density showed dependence on the Fe fraction; however, the dependence of specific current density with Fe fraction is not linear.We believe that the iron incorporation in the La0.6Ca0.4CoO3 perovskites decreases the electron transfer barrier and facilitates the formation of cobalt-hydroxides.
| Original language | English |
|---|---|
| Pages (from-to) | F1124-F1132 |
| Journal | Journal of the Electrochemical Society |
| Volume | 163 |
| Issue number | 9 |
| DOIs | |
| State | Published - 2016 |
Funding
This research has been supported by the NSF-IGERT DGE-0966089 at the University of Rochester, NY. A portion of this research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy. Support (MPP and CAB) for neutron characterizations was provided by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. DAT acknowledges support by the New Energy and Industrial Development Organization (NEDO) of Japan. Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).