Correlating atomic-scale structural and compositional details of Ca-doped LaCoO3 perovskite nanoparticles with activity and stability towards the oxygen evolution reaction
Fan Bai, Jonas Schulwitz, Tatiana Priamushko, Ulrich Hagemann, Aleksander Kostka, Markus Heidelmann, Serhiy Cherevko, Martin Muhler, Tong Li
Abstract
Developing efficient oxygen evolution reaction (OER) electrocatalysts requires a thorough understanding of structure–activity-stability relationships, ideally at the atomic scale. Herein, we employed atom probe tomography and transmission electron microscopy to reveal compositional and structural changes on LaCoO3 and Ca-doped LaCoO3 surfaces during OER. We reveal that the topmost surfaces of pristine perovskite are terminated by the A-site element (La). After OER, amorphous La(OH)3 is formed on the surfaces of LaCoO3, which leads to significant activity deterioration. For Ca-doped LaCoO3, enhanced intercalation and penetration of hydroxide ions, along with the appearance of Co3+/4+ redox couple, are observed, contributing to its enhanced OER activity and stability. Our study demonstrates how atomic-scale compositional and structural details of electrocatalyst surfaces deepen our understanding of their activity and stability.