Effect of oxygenation on electrocatalysis of La0.6Ca0.4CoO3-x in bifunctional air electrode
Journal
Electrochimica Acta
Journal Volume
48
Journal Issue
11
Pages
1567-1571
Date Issued
2003
Author(s)
Abstract
A vacuum-annealed La0.6Ca0.4CoO3-x was consecutively oxygenated in air at temperatures decreasing from 800 to 100 °C, and its electrocatalytic activities for oxygen reduction and evolution were then measured as a function of the oxygenation temperature. The valence of Co cation, changing between +2 and +3, was found susceptible to annealing either in vacuum or air. The catalytic activities initially decrease monotonically as the oxygenation temperature was decreased from 800 to 300 °C, as a result of increasing oxygen content, and then rise abruptly with the oxygen reduction activity reaching a maximum at 200 °C and the oxidation activity at 150 °C. X-ray photoelectron spectroscopy analysis indicated that the enhancements by the low-temperature oxygenation involved increased OH coverage and less charged cations at surface. The results clearly reveal the importance of the post-calcination annealing process for optimizing the performance of La0.6Ca0.4CoO3-x in air electrode applications. © 2003 Elsevier Science Ltd. All rights reserved.
SDGs
Type
journal article