Oxygen and hydrogen peroxide electroredn. on La0.6Ca0.4CoO3 perovskite electrodes was studied in alk. media. Rotating disk electrodes were built using pure powders of the oxide to avoid any side reactions on the catalyst support, e.g. carbon. For O2 redn., Koutecky-Levich plots showed a curvature at high rotation speeds (w), and the corresponding no. of electrons exchanged (n) varied from 1.3 to 2, depending on w. This behavior indicates that the main part of the oxygen was reduced via the 2 e- path, leading to H2O2. Concerning hydrogen peroxide redn., the measurements were affected by the chem. decompn. of H2O2 at the perovskite electrode producing O2. The heterogeneous chem. decompn. of hydrogen peroxide was studied for La0.6Ca0.4CoO3 powders prepd. at different temps. The H2O2 decompn. rate was found to vary strongly with sintering temp. of the La0.6Ca0.4CoO3 catalyst. [on SciFinder (R)]