Enhancing Oxygen Exchange Activity by Tailoring Perovskite Surfaces

Abstract

A detailed understanding of the effects of surface chemical and geometric composition is essential for understanding the electrochemical performance of the perovskite (ABO₃) oxides commonly used as electrocatalysts in the cathodes of ceramic fuel cells. Herein, we report how the addition of submonolayer quantities of A- and B-site cations affects the rate of the oxygen reduction reaction (ORR) of Sr-doped LaFeO₃ (LSF), LaMnO₃ (LSM), and LaCoO₃ (LSCo). Density functional theory calculations were performed to determine the stability of different active sites on a collection of surfaces. With LSF and LSM, rates for the ORR are significantly higher on the A-site terminated surface, while surface termination is less important for LSCo. Our findings highlight the importance of tailoring the surface termination of the perovskite to obtain its ultimate ORR performance.