Growth mechanism and photocatalytic activity of chrysanthemum-like anatase TiO2 nanostructures

Chrysanthemum-like hierarchical anatase TiO2 nanostructures self-assembled by nanorods have been successfully fabricated by a simple solvothermal route without using template materials or structure-directing additives. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectrometer system (Raman), UV-vis absorption spectroscopy (UV-vis) and N2 adsorption-desorption measurement. The results indicate that synthesized chrysanthemum-like hierarchical anatase TiO2 nanostructures have a spherical shape with an average diameter of 1.5 μm and they are composed of nanorods with a width of about 30 nm and a length of about 300 nm. The pore distribution of the sample exhibits two kinds of pores. Such mesoporous structure of the sample might be extremely useful in photocatalysis because they possess efficient transport pathways to the interior and supplies higher specific area for more pollutant molecules to be absorbed. In addition, the synthesized TiO2 nanostructures show enhanced photocatalytic activity compared with commercial P25 for the degradation of RhB under UV light irradiation, which can be attributed to their special hierarchical structure and high light-harvesting capacity.