Oxygen (O2) reduction reaction on Ba-doped LaMnO3 cathodes in solid oxide fuel cells: a density functional theory study

• Published in: Materials for renewable and sustainable energy Vol. 10; no. 4; pp. 1 - 10
• Main Authors: Aniagyei, Albert, Kwawu, Caroline, Kwakye, Ralph, Antwi, Boniface Yeboah, Osei-Owusu, Jonathan
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-12-2021; Springer Nature B.V; SpringerOpen
• Subjects: Adsorption; Barium; Cathodes; Cations; Chemical reduction; Chemistry and Materials Science; Density functional theory; Exothermic reactions; Gibbs free energies; Iridium; LaMnO3; Lanthanum compounds; Materials Science; Operating temperature; Original Paper; Oxygen; Oxygen reduction reactions; Palladium; Peroxide; Precursors; Renewable and Green Energy; SOFC; Solid oxide fuel cells; Superoxide; Surface chemistry; Superoxide; Peroxide; LaMnO; Gibbs free energies; SOFC
• ISSN: 2194-1459; 2194-1467
• DOI: 10.1007/s40243-021-00200-1

The oxygen adsorption and subsequent reduction on the {100} and {110} surfaces of 25% Ba-doped LaMnO
3
(LBM25) have been studied at the density functional theory (DFT) with Hubbard correction and the results compared with adsorption on 25% Ca-doped LaMnO
3
(LCM25) and Sr-doped LaMnO
3
(LSM25). The trend in the reduction energies at the Mn cation sites are predicted to be in the order LSM25 < LBM25 < LCM25. In addition, the trend in dissociation energies for the most exothermic dissociated precursors follow the order LBM25 < LSM25 < LCM25. The adsorption energies (− 2.14 to − 2.41 eV) calculated for the molecular O
2
precursors at the Mn cation sites of LCM25, LSM25 and LBM25 are thermodynamically stable, when compared directly with the adsorption energies (
E
ads
 = − 0.56 to − 1.67 eV) reported for the stable molecular O
2
precursors on the Pt, Ni, Pd, Cu and Ir {111} surfaces. The predicted Gibbs energies as a function of temperature (
T
 = 500–1100 °C) and pressures (
p
 = 0.2 atm) for the adsorption and dissociation on the surfaces were negative, an indication of the feasibility of oxygen reduction reaction on the {100} and {110} surfaces at typical operating temperatures reported in this work.