Controlled synthesis of heterogeneous metal-titania nanostructures and their applications.

We describe a new synthetic approach to heterogeneous metal-TiO(2) nanomaterials based on conversion of Ti(3+) to hydrous TiO(2) occurring uniquely on the nanostructured metallic surfaces such as Pt, Au, and Ni nanowires and nanoparticles. The TiO(2) growth mechanism was studied by designing an electrochemical cell. A variety of heterogeneous metal-TiO(2) nanostructures, such as segmented metal-TiO(2) nanowires, core-shell metal-TiO(2) nano/microparticles, and composite metal-TiO(2) nanotubes, can be fabricated by varying the morphology of the seeding metal nanostructure or controlling selective TiO(2) growth on different surfaces of the metallic nanomaterial. Altering the reaction time and Ti(3+) concentration allows the TiO(2) segment lengths or TiO(2) shell thicknesses to be finely tuned. Coaxial Au-TiO(2) nanorod arrays were demonstrated to be fast lithium-ion storage materials, while the core-shell Ni-TiO(2) nanoparticles exhibited excellent photodegradation properties as magnetic recyclable photocatalysts.