Polyoxometalate-assisted electrochemical deposition of hollow ZnO nanospheres and their photocatalytic properties

Uniform zinc oxide hollow spheres with diameters of about 200-300 nm and shells composed of nanoparticles were fabricated in large scale by a one-step polyoxometalate (POM)-assisted electrochemical method at room temperature. A series of experiments demonstrated that the addition of POMs, the concentration of H2O2 and reaction time all had significant effect on the morphology of the products. The products were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The photocatalytic activity of as-prepared ZnO hollow spheres was also evaluated by using Rhodamine (RhB) as a model organic compound and the result revealed that the products showed high photocatalytic activity to degradation of Rhodamine (RhB) under UV-light illumination. Based on the evolution of the ZnO hollow spheres and the electrochemical principle, a rational formation and evolution mechanism of the products was revealed. (C) 2010 Elsevier Inc. All rights reserved.