Dataset of "Gelatine-assisted Defect Engineering in LaCoO3 and its Impact on Oxygen Electrocatalysis"

Nanocrystalline LaCoO3 materials prepared by spray-freeze freeze-drying approach in the presence of various amounts of gelatine were tested in oxygen electrocatalysis in alkaline media. The presence of gelatine in the reaction mixture affects the distribution of the oxygen vacancies as well as formation of Ruddlesen–Popper (RP) defects within nanocrystals. The materials prepared at low gelatine concentration (c  1.5g/L) tend to locate the oxygen vacancies  at the domain boundaries while increasing gelatine concentration promotes a larger formation of superstructure where the  oxygen vacancies get ordered along the {100] pseudocubic direction in the crystal. The ordered vacancies as well RP faults are primary sites of exfoliation in acid media steering the electrocatalytic behavior of the prepared materials in both oxygen evolution and oxygen reduction. The exfoliation significantly promotes the OER activity via a new surface formation increasing the presence of Co (III) - Co (IV) species at the surface which are responsible for oxygen evolution. The exfoliation, on the other hand, leads to a change of the ORR mechanism promoting four-electron reduction over the two-electron peroxide formation. This behavior can be attributed to a change of reactivity of the exfoliated surfaces which apparently adsorb peroxo intermediates more strongly than as prepared materials.