Assembly synthesis of Cu2O-on-Cu nanowires with visible-light-enhanced photocatalytic activity.

New Cu2O-on-Cu nanowires (NWs) are constructed to develop the visible-light-driven activity of photocatalysts via the facile self-assembly of Cu2O nanoparticles (NPs) on a Cu NW surface assisted by a structure director, followed in situ reduction. In the resultant Cu2O-on-Cu NWs, the Cu2O NPs, with a diameter of 10 nm, show good distribution on the 50 nm-sized Cu single-crystal NWs. Owing to the band-gap adjusting effect and high electron transportation, the coupling of narrow-band-gap semiconductor Cu2O and excellent conductor Cu can lead to the markedly enhanced high visible light photocatalytic activity of Cu2O-on-Cu NWs toward the degradation of dye pollutants including Rhodamine B (RhB), methyl orange (MO) and methyl blue (MB). The as-designed Cu2O-on-Cu heterostructured NWs exhibit higher performance for the catalytic degradation of dye compounds than pure Cu2O. Nearly 60%, 100%, and 85% conversion with reaction rate constants (k) of 0.0137, 0.0746 and 0.0599 min(-1) can be achieved for the degradation of RhB, MO and MB, respectively. Besides the highly efficient transportation of electrons, Cu NWs have a strong capacity for oxygen activation, which results in the gathering of negative charges and rich chemisorbed oxygen onto the surface. This may be responsible for the high catalytic efficiency of the Cu2O-on-Cu NWs toward the degradation of organic pollutants.