Optimizing Surface Electronic Structure by Ba Dispersion for Enhanced High-Temperature Oxygen Evolution Reaction Activity

Surface modification is an advanced strategy to engineer and optimize the work function of the perovskite oxides, which can influence the surface electron and ion transfer processes and tune the surface adsorption of the reaction intermediates, thus enhancing the catalytic activity by creating more active sites. Herein, we modify the surface electronic structure of the Pr_0.9CoO_3-δ anode of the solid oxide electrolysis cells (SOECs) by the high-temperature dispersion of Ba species. Comprehensive structural and electrochemical characterizations, along with in situ characterizations and density functional theory calculations, reveal that Ba dispersion significantly enhances the surface d-p orbital hybridization between Co and O atoms and thus weakens Co-O bond covalency, facilitating oxygen vacancy formation and oxygen ion mobility. Electrochemical testing demonstrates that the Ba-dispersed anode exhibits significantly reduced polarization resistance and superior high-temperature oxygen evolution reaction activity with a current density of 3.36 A·cm^-2 at 1.6 V and 800 °C. These findings provide a novel strategy for engineering surface electronic structures to enhance SOEC performance, offering insights into rational catalyst design for efficient energy conversion applications.