Porous Perovskite-Type Lanthanum Cobaltite as Electrocatalysts toward Oxygen Evolution Reaction

Porous lanthanum cobaltite (LaCoO 3 ) was prepared by hydrothermal reaction and converted into hollow nanospheres through heat treatment. These hollow spheres were examined as electrocatalysts toward oxygen evolution reaction (OER) using the rotating disk electrode technique in an alkaline solution. The obtained mass-specific OER activity was 7.51 A/g for porous LaCoO 3 particles and 12.58 A/g for hollow LaCoO 3 nanospheres at 1.60 V. These values were more than 4–6 times higher than that of bulk LaCoO 3 compound (1.87 A/g). The OER performance of these perovskite-type LaCoO 3 compounds was characterized using the Tafel equation, which showed the hollow nanospheres had the fastest kinetics among the three morphologies. The amorphous surface of these porous structures could contribute to the enhanced OER performance. The electrocatalytic and structural analysis results show the porous nanostructures with amorphous surface layers are important to achieve high activity toward OER for water splitting.