Assembly of TiO₂ -on-Cu₂ O Nanocubes with Narrow-Band Cu₂ O-Induced Visible-Light-Enhanced Photocatalytic Activity

Newly designed TiO₂ -on-Cu₂ O nanocubes have been constructed as visible-light-driven photocatalysts with high efficiency by means of a facile self-assembly approach at room temperature. In the resultant TiO₂ -on-Cu₂ O nanocubes, the TiO₂ nanoparticles with a diameter of 6-8 nm show a well-monodispersed distribution of the 200-300 nm-sized Cu₂ O single-crystal nanocubes, which can form sub-monolayer, monolayer, and multilayer coverage through controlling the ratio of the two phases. In particular, the coupling of the wide-bandgap semiconductor TiO₂ with narrow-bandgap Cu₂ O can lead to the markedly enhanced high visible-light photocatalytic activity in the TiO₂ -on-Cu₂ O nanocomposite systems toward the photodegradation of rhodamine B, which is induced by the bandgap-adjusting effect. This promising self-assembly route can be extended to the preparation of other nanocomposite materials.