Nanocrystalline TiO2 on single walled carbon nanotube arrays: Towards the assembly of organized C/TiO2 nanosystems

Arrays of single walled carbon nanotube bundles organized following different architectures have been coated by a homogeneous deposit of nanocrystalline titania. The nanotubes were grown treating nanosized C powders with atomic H in a purpose-designed chemical vapor deposition (CVD) reactor, the subsequent TiO₂ deposition was performed at 400 °C using the metal-organic CVD (MOCVD) technique and titanium tetraisopropoxide Ti(OⁱPr)₄ as a precursor. X-ray diffraction and Raman spectroscopy evidence the anatase structure of the TiO₂ coatings, formed by grains with an average size of about 55 nm. The structural and compositional characteristics of the TiO₂ deposits are not sensitive to the organization of the nanotube arrays, which maintain their pristine architectures. The adopted synthetic procedure opens a new route for the immobilization of anatase-type TiO₂ nanocrystallites onto geometrically varied structures and for the integration of composite nanotube/TiO₂ systems in effective devices.