An innovative method to quickly and simply prepare TiO2 nanorod arrays and improve their performance in photo water splitting

Abstract

Abstract We developed a simple way to synthesize TiO 2 nanorod array on a Ti foil under moderate conditions in an ambient atmosphere. The morphology of the TiO 2 nanostructure synthesized by titanium salts and acids depends on the type of acid and Ti precursors. The growth of rutile TiO 2 nanorods with a diameter of 20–180 nm on a Ti foil was obtained when Ti foil was treated in the presence of TiCl 4 and HNO 3 . The diameters and growth rates of TiO 2 nanorods increased with increasing concentrations of HNO 3 and Ti precursor. As a consequence, these factors can easily be tuned to generate the desired TiO 2 nanorod array in this proposed process. By calcining at a temperature of 550 °C, the TiO 2 nanorod arrays exhibited optimal photocatalytic activity due to an oriented nanorod structure and good crystallinity. The photoconversion efficiency is a function of array thickness and nanorod morphology. Due to an oriented nanorod structure beneficial to electron transfer, the TiO 2 nanorod array has a maximum photoconversion efficiency of 8.65% higher than that of the compact nanoparticle film of 2.33%.