Low temperature fabrication of nanoflower arrays of rutile TiO2 on mica particles with enhanced photocatalytic activity

In this work, nanoflower arrays of rutile TiO2 composed of nanorods were directly grown onto mica substrates through hydrolysis of TiCl4 ethanolic solution in water at 70 °C without calcination. SnO2 as a rutile promoting additive was deposited onto mica prior to TiO2. The rutile promoting effects of SnO2 could be ascribed to the structural similarity of rutile and cassiterite. The nanorod crystals grew along the [0 0 1] direction, forming predominantly exposed {1 1 0} side-facets and {0 1 1} top-facets. A reasonable growth mechanism for elucidating the formation of rutile TiO2 nanoflower arrays was proposed. The obtained nanoflower arrays of rutile TiO2 coated mica particles show excellent photocatalytic activity towards degradation of rhodamine B (RhB) under UV illumination, which is almost 1.9 times as high as that of Degussa P25. The enhanced photocatalytic activity of rutile TiO2 superstructures can be ascribed to the combined contribution of high crystallinity, low band gap, and effective separation of electrons and holes by the synergistic effect between the exposed {1 1 0} and {0 1 1} facets of the rutile nanorods. Furthermore, we demonstrated that these rutile TiO2 coated mica particles can be easily recycled without decrease of the photocatalytic activity, which provide possibility to future industrial applications in environmental pollutants cleaning up.