Highly dispersed LaCoO₃ on carbon prepared via low-energy bead milling as an oxygen reduction electrocatalyst

In this study, fine dispersion of LaCoO₃ nanoparticles on carbon via low-energy bead milling was attempted. X-ray diffraction and scanning transmission electron microscopy revealed that LaCoO₃ nanoparticle agglomerates formed by high-temperature calcination were broken up by milling with small beads at low rotation rate, while suppressing damage to the crystal structure. The low-energy bead-milled LaCoO₃/carbon exhibited 2.7 times higher kinetic current density for the oxygen reduction at −0.15 V vs. Hg/HgO than as-synthesized LaCoO₃/carbon; this enhancement may be attributed to the enlarged surface area and improved dispersion of the oxide on carbon.