Controlled Synthesis of Heterogeneous Metal-Titania Nanostructures and Their Applications

We describe a new synthetic approach to heterogeneous metal-TiO2 nanomaterials based on conversion of Ti3+ to hydrous TiO2 occurring uniquely on the nanostructured metallic surfaces such as Pt, Au, and Ni nanowires and nanoparticles. The TiO2 growth mechanism was studied by designing an electrochemical cell. A variety of heterogeneous metal-TiO2 nanostructures, such as segmented metal-TiO2 nanowires, core-shell metal-TiO2 nano/microparticles, and composite metal-TiO2 nanotubes, can be fabricated by varying the morphology of the seeding metal nanostructure or controlling selective TiO2 growth on different surfaces of the metallic nanomaterial. Altering the reaction time and Ti3+ concentration allows the TiO2 segment lengths or TiO2 shell thicknesses to be finely tuned. Coaxial Au-TiO2 nanorod arrays were demonstrated to be fast lithium ion storage materials, while the core-shell Ni-TiO2 nanoparticles exhibited excellent photodegradation properties as magnetic recyclable photocatalysts.