Prediction of Surface Oxygen Vacancy Concentrations of (La_1-xSr_x)MnO₃

Perovskite materials of the form ABO₃ are an important family of compounds for use in solid oxide fuel cell (SOFC) cathodes. In particular, their surface properties play an essential role in their catalytic ability. This paper combines bulk defect models fit to experimental data with ab initio surface energies to predict surface vacancy concentrations in (La_1-xSr_x)MnO₃. It is found that the surface vacancy concentration is ~10⁶ times that of bulk under SOFC operating conditions. The enhanced concentration of surface vacancies may play a role in O₂ dissociation, incorporation, and surface transport.