Hierarchical Flower-Like Nanostructures of Rutile TiO2 and Their Photocatalytic Activity

We report the synthesis of hierarchical flower-like TiO2 nanostructures using microwave assisted hydrothermal technique. This technique provides a unique control over the reaction temperature. Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-Vis spectroscopy have been used to characterize the resulting nanostructured TiO2. The XRD results show that the TiO2 nanostructures have tetragonal rutile phase with very small amount of anatase phase at lower reaction temperature. The FE-SEM micrographs show three dimensional flowers like nanostructures consist of several nanorods coming out of a single core and have sharp edges. The effect of the preparation temperature on the decolorization ability of reactive methylene blue by photocatalysis under UV light was investigated. The photocatalytic properties of the samples shows that the sample that has a high aspect ratio (AR similar to 12.96) has a much better photocatalytic activity as compared to the sample of the low aspect ratio (AR similar to 6.2). The optimal synthesis temperature was obtained at about 175 degrees C to get the high aspect ratio TiO2 nanocrystals.