Photocatalytic activities of TiO2 nanoparticles modified by nanoclusters of copper oxides prepared by atomic layer deposition

We employed atomic layer deposition to deposit nanoclusters of Cu2O on TiO2 nanoparticles to produce TiO2/Cu2O photocatalysts with the Cu concentration in the range of 0.4 - 4.6%. By annealing the TiO2/Cu2O photocatalysts in the air at 400 °C for 4 h, the oxidation of Cu2O resulted in the formation of TiO2/CuO photocatalysts having the same Cu concentration. Transmission electron microscopy and X-ray diffraction characterizations demonstrated the successful deposition of Cu2O nanoclusters with an average diameter in the range of 1.3 - 2.0 nm and a face-centered cubic crystalline structure, whereas a weak signal of the monoclinic structure of CuO was detected for the TiO2/Cu2O catalysts. The photocatalytic activity of the TiO2/Cu2O and the TiO2/CuO photocatalysts was investigated by the degradation of RhB under UV radiation. The results show that the presence of Cu2O and CuO nanoclusters could improve the photocatalytic activity of TiO2, and for the same Cu concentration, the TiO2/Cu2O photocatalyst provided higher catalytic activity than the TiO2/CuO counterpart.