Three-dimensional (3D) flower-like nanoarchitectures of ZnO-Au on MWCNTs for visible light photocatalytic applications

Nanoflower-like ZnO-Au (zinc oxide/gold) composites were grown on multiwall carbon nanotubes (MWCNT) for visible light functioning plasmonic photocatalysis via a simple wet chemical strategy. Pristine ZnO were also grown in the absence/presence of MWCNTs for comparative studies. The appearance of ZnO-Au and ZnO on MWCNTs were noted to be in flower form. The dimension of ZnO-Au nanoflowers on MWCNTs were measured to be around 350 nm by electron microscopy. Their structural studies revealed the hexagonal wurtzite structure of ZnO to be predominant. UV-vis absorbance measurements revealed a significant enhancement in the absorption of visible region photons in ZnO when composited with MWCNTs and Au. The photocatalytic studies carried out under sun light illumination demonstrated the enhanced activity of ZnO-Au systems grown on MWCNTs rather than that of ZnO or MWCNT/ZnO. The improved photocatalytic activity has been reasoned to the effective band alignment and transportation of electrons from MWCNTs and Au to the conduction band of ZnO.