Fabrication of micrometer-scale spherical titanate nanotube assemblies with high specific surface area

Three-dimensional (3D) micrometer-scale spherical titanate nanotube assemblies have been successfully synthesized via hydrothermal synthesis from Ti powders. The obtained titanate nanotube assemblies have a diameter of around 4–7 µm. The titanate nanotubes have an outer diameter of around 9–10 nm, an inner diameter around 3–4 nm and a length of several micrometers. A proposed two-stage growth mechanism was applied to explain the formation process of these titanate nanotube assemblies. We have also demonstrated that these titanate assemblies have higher specific surface area and larger adsorption capacity than that of titanate nanotubes. And they could possibly be further used in photocatalysts, separation technologies, energy-storage technologies and so on.