A facile fabrication of a uniform and homogeneous CNT–TiO2 composite: a microscopic and scattering investigation
We demonstrated a facile and robust two-step method to fabricate a carbon nanotube–titania nano composite using spray hydrolysis and a chemical vapour deposition (CVD) technique with control over the morphology and deposition chemistry of reaction. Hierarchically structured NiO doped TiO2 submicrospheres have been realized by hydrolysis of titanium alkoxide at the water–oil interface of micrometer sized droplets. Utilizing these TiO2 microspheres, a composite of TiO2–CNT has been synthesized through the CVD technique. Mesoscopic structural investigations have been carried out on composites using ultra small-angle neutron scattering, and small-angle X-ray scattering. There exist three distinct length scales in the composite microspheres. Thermal evolution of microstructure was investigated by in situ X-ray diffraction which clearly indicates an amorphous to crystalline transition of TiO2. It is established that the polymorphic phase transition of TiO2 nanoparticles is associated with the increase in its size. Microscopic studies showed that the TiO2 substrate has given a uniform growth surface for CNTs. Furthermore, their growth mechanism has been discussed.