ZnO nanostructures are grown using zinc acetate and zinc nitrate as precursors on patterned sapphire substrate by aqueous method in this paper. Structural and optical properties of ZnO nanostructures are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and photoluminescence (PL). The photocatalytic activities of the as-prepared samples are evaluated by photocatalytic decolorization of Methyl orange. It has been found that the distinct surface morphologies of ZnO nanostructures grown by different precursors. ZnO nanoflowers arrays with a hexagonal wurtzite structure are grown by using zinc nitrate as precursors, whereas ZnO nanorods/film hybrid structures are achieved by zinc acetate. Meanwhile, both ZnO samples show remarkable photocatalytic activity, in particular, ZnO nanoflowers arrays exhibit an outstanding photocatalytic activity. This behavior is mainly due to the high surface-to-volume ratio and high content of oxygen vacancy, which is also confirmed by photoluminescence. This investigation may provide guidance for the morphology-controlled synthesis of ZnO nanostructures grown on patterned sapphire and their application in the treatment of organic pollutants. (C) 2012 Elsevier B.V. All rights reserved.