Understanding Structural Incorporation of Oxygen Vacancies in Perovskite Cobaltite Films and Potential Consequences for Electrocatalysis

Owing to their excellent mixed-ionic and electronic conductivity, fast oxygen kinetics, cost efficiency, layered oxygen-deficient perovskite oxides hold great potential as highly efficient cathodes for solid oxide fuel cells anodes water oxidation. Under working conditions, cation ordering is believed substantially enhance diffusion while maintaining structural stability owing the formation of double (DP), thus attracting extensive research attention. In contrast, incorporation vacancies associated vacancy have rarely been studied at atomic scale, despite decisive roles in regulating spin structures well differentiating crystal structure from DP. Here, atomic-resolution transmission electron microscopy used directly image measure concentration (Pr,Ba)CoO3-δ films grown on SrTiO3 substrates. We find that accompanied by presence Co–O planes, A–O (A = Pr/Ba) planes also exhibit a breathing-like lattice modulation. Specifically, confirmed first-principle calculations, AO–AO interplanar spacings are found be linearly correlated with enclosing planes. On this basis, consequences occupancy catalytic properties structurally pure PBCO phases discussed. Through establishing simple correlation easily achievable measurement, our results pave way better understanding structure–performance relationship complex cobaltites electrocatalysis.