Fabrication and visible light photocatalytic activity of Co-doped ZnO nanorods

Co-doped ZnO nanorods were prepared by electrochemical deposition method in aqueous solution. To study the as-grown samples, several characterizations were carried out. The scanning electron microscopy(SEM) images show that the samples present a rod-like shape with hexagonal cross sections and roughened surface. There is a slight shift for (002) diffraction peak of Co-doped ZnO nanorods in XRD because Co2+ ions entered into the ZnO lattice. Energy-dispersive X-ray spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) results also show the exist of Co in the sample. Photoluminescence(PL) spectra of the samples were observed at room temperature, the UV emission of Co-doped ZnO shows a slight red shift compared with that of undoped ZnO. Thus, we can reach the conclusion that Zn2+ ions have been substituted by Co2+ ions in the ZnO samples. In addition, photocatalysis property of Co-doped ZnO nanorods was investigated under the irradiation of visible light. It was found that the degradation rate of methyl orange is increased greatly by Co-doped ZnO nanorods in comparison to undoped ZnO nanorods.