Assembly of TiO2‐on‐Cu2O Nanocubes with Narrow‐Band Cu2O‐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.