Enhanced sunlight photocatalytic activity of porous TiO2 hierarchical nanosheets derived from petal template

The petal with delicate microstructures is a natural material. An attempt has been made in this study to prepare mesoporous titanium dioxide nanosheets derived from bio-membranes contained in the rose petal cytoderm via a continuous infiltration process of diluted TiCl4 aqueous solution. The as-synthesized bio-morphic films are distinguished by the tetragonal phase of TiO2, consisting of uniform nanocrystals of anatase. FESEM, HRTEM, and AFM analyses results revealed that these hierarchical nanostructures were built from two-dimensional porous nanosheets with a thickness of ca. 4 nm. UV–Visible diffuse reflectance spectra of the bio-morphic TiO2 indicate that the unique nanostructures are endowed with high light-harvesting efficiency, especially in the region from 400 nm to 600 nm. Moreover, the prepared hierarchical plate-like TiO2 films showed enhanced photocatalytic activity compared with Degussa P25 for the degradation of methylene blue under sunlight irradiation. The enhancement in photocatalytic properties could be attributed to hierarchical porous structures and the extremely small thickness. These results could provide useful inspirations for the synthesis of further high performance photocatalysts and reveal potential applications based on biomimicking the natural plant structures.