Durability of Carbon-Supported La-Mn-Based Perovskite-Type Oxides as Oxygen Reduction Catalysts in Strong Alkaline Solution

The durability of carbon-supported La-Mn-based perovskites for the oxygen reduction reaction in strong alkaline solutions was investigated. Carbon-supported perovskite-type oxide nanoparticles were prepared by using a reverse micelle method. The durability of the carbon-supported LaMnO 3 nanoparticles was compared with that of carbon-supported LaMnO 3 prepared by the mechanical mixing of LaMnO 3 with the carbon support. As a result, the durability of the carbon-supported LaMnO 3 nanoparticles was less than that of the carbon-supported LaMnO 3 prepared by the mixing method due to a difference in the surface area of LaMnO 3 , which has an effect on the oxygen reduction reaction. In order to improve the durability of the carbon-supported LaMnO 3 nanoparticles, Ca and Fe were substituted at the A-sites and B-sites of the perovskite lattice, respectively. As a result, it was found that the partial substitution of Ca and Fe is effective in improving the durability of LaMnO 3 under cathodic polarization in strong alkaline solutions. In particular, the substitution of Ca at the A-site not only improved the durability of the oxide but also enhanced the oxygen reduction activity owing to an increase in the average valence state of the B-sites of the perovskite lattice.