Atomic-Scale Insights into Surface Lattice Oxygen Activation at the Spinel/Perovskite interface of Co3 O4 /La0.3 Sr0.7 CoO3.

ABSTRACT

Surface lattice oxygen in transition-metal oxides plays a vital role in catalytic processes. Mastering activation of surface lattice oxygen and identifying the activation mechanism are crucial for the development and design of advanced catalysts. A strategy is now developed to create a spinel Co3 O4 /perovskite La0.3 Sr0.7 CoO3 interface by in situ reconstruction of the surface Sr enrichment region in perovskite LSC to activate surface lattice oxygen. XAS and XPS confirm that the regulated chemical interface optimizes the hybridized orbital between Co 3d and O 2p and triggers more electrons in oxygen site of LSC transferred into lattice of Co3 O4 , leading to more inactive O2- transformed into active O2-x . Furthermore, the activated Co3 O4 /LSC exhibits the best catalytic activities for CO oxidation, oxygen evolution, and oxygen reduction. This work would provide a fundamental understanding to explain the activation mechanism of surface oxygen sites.