Electrochemically prepared cuprous oxide film for photo-catalytic oxygen evolution from water oxidation under visible light

Photo-catalytic oxygen evolution from water oxidation is very important for solar energy utilization and fuel cell production. In this work, cuprous oxide film for photo-catalytic water oxidation and oxygen evolution under visible light was in-situ prepared on a copper foil with an anodization based method. The surface features of cuprous oxide film were characterized with X-ray diffraction and scanning electron microscopy. The oxygen evolution capacity of as-obtained cuprous oxide film was evaluated with a water photolysis system, and an oxygen yield of 233.27 μmol per milligram of cuprous oxide was achieved during 8 h of illumination. During the reaction, water was oxidized by the photo-generated holes in cuprous oxide, and the copper/cuprous oxide heterojunction can effectively separate the photo-generated electron-hole pairs, which promote the catalytic activity of cuprous oxide film. The oxygen evolution reaction was driven by the bending of energy band of cuprous oxide caused by the semiconductor-metal contact. The remaining protons by the water oxidation resulted in the acidizing of water.