Large‐Scale Synthesis and Characterization of TiO 2 ‐Based Nanostructures on Ti Substrates

Na 2 Ti 6 O 13 nanoplates, nanowires, and continuous nanowire network films are hydrothermally formed on a large scale directly on Ti substrates for the first time. The morphology of the formed Na 2 Ti 6 O 13 nanostructures can be easily tuned by varying the experimental parameters of temperature, reaction duration, and the NaOH concentration. Our study demonstrates that the synthesized Na 2 Ti 6 O 13 nanostructures are easily converted into H 2 Ti 3 O 7 nanostructures—a desirable precursor for the fabrication of various TiO 2 ‐based nanomaterials—with shape preservation, by an ion‐exchange process. Anatase, a mixture of anatase and rutile, and rutile TiO 2 nanowires are formed when the H 2 Ti 3 O 7 nanowires are annealed at 450, 600, and 750 °C, respectively. The optical properties and the photocatalytic activity of H 2 Ti 3 O 7 nanowires and of the TiO 2 ‐based nanomaterials are also addressed. The approach described in this study provides a simple and novel method for the large‐scale synthesis of various TiO 2 ‐based nanostructured materials that grow directly on Ti substrates and are ready for a wide range of practical applications, such as the photodegradation of wastewater.