The effect of the preparation procedure on the morphology, texture and photocatalytic properties of ZnO

Abstract This paper focuses on the modification of ZnO properties by changes in the preparation procedures, which determine the surface and photocatalytic properties. A diversity of morphologies, structural/textural and surface properties of ZnO was achieved by using three different synthetic procedures: the sol-gel method, the precipitation method with the use of oxalic acid, and a solvent evaporation procedure. The degree of crystallinity, particle size, porosity, band gap energy, and the presence and types of defect sites were measured and correlated to the preparation procedure and photocatalytic activity toward Rhodamine B (RhB) degradation. It was found that the preparation method and the use of a re-dispersion route strongly influence the ZnO morphology. In turn, the morphology determines the nature and density of surface defects. The highest photocatalytic activity towards RhB decomposition is exhibited by ZnO prepared by the precipitation method. The reaction rate is strongly affected by the crystallinity of the ZnO.