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Role of Adsorbate Coverage on the Oxygen Dissociation Rate on Sr-Doped LaMnO 3 Surfaces in the Presence of H 2 O and CO 2
Name
acs.chemmater.9b05243.pdf
Description
Published version
Size
4.4 MB
Format
Adobe PDF
Checksum (MD5)
1adafd3a314b5e15806c271853f514b4
Author(s)
Yang, Jing
Polfus, Jonathan M
Li, Zuoan
Tuller, Harry L
Yildiz, Bilge
Journal
Chemistry of Materials
Publisher
American Chemical Society (ACS)
Version
Final published version
Abstract
Copyright © 2020 American Chemical Society. Sr-doped LaMnO3 (LSM) is a promising oxygen reduction reaction electrocatalyst in solid oxide fuel cells and other electrochemical devices. The presence of CO2 and H2O has been reported to promote the oxygen dissociation reaction on LSM surfaces. Here, we investigate the coadsorption mechanism of O2 with H2O or CO2 by combining first-principles calculations of the (0 0 1) surface containing 25-100% Sr with thermodynamic adsorption models. The molecules were found to chemisorb by formation of charged oxygen, hydroxide, and carbonate species, and the adsorption energies were exothermic up to monolayer coverage. Low concentrations of H2O or CO2 do not compete with O2 for adsorption sites under relevant conditions. However, their presence contributes to the total amount of oxygen-containing species. The increased coverage of oxygen species provides a quantitative explanation for the reported enhancement in oxygen dissociation kinetics in the presence of H2O/CO2. This study thereby provides insights into oxygen exchange mechanisms on LSM surfaces.
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
10.1021/ACS.CHEMMATER.9B05243
