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.