Oxidation of water is a challenging process with a positive free energy change and it is purposeful to find good catalysts to facilitate the process. While the perovskite oxides, LaCoO3 and LaMnO3, are good electron transfer catalysts in artificial photosynthesis to produce oxygen by the oxidation of water, the electron transfer is further favoured by the presence of platinum nanoparticles, causing a substantial increase in oxygen evolution.