Structural investigations of hybrid TiO 2/CNTs nanomaterials

In the present study, pure TiO ₂ and hybrid TiO ₂/CNTs nanomaterials are prepared by sol gel technique. Post heat treatment is performed at 600, 800, and 1000 °C, respectively. The structural characterizations are performed by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and synchrotron X-ray absorption spectroscopy techniques. Experimental results show that anatase to rutile transformation can be observed for pure TiO ₂ nanomaterials after heat treatment at 800 °C. The anatase to rutile transformation is inhibited by carbon nanotubes, and therefore only anatase phases for TiO ₂ nanomaterials can be observed in the hybrid nanomaterials. The 600 °C hybrid nanomaterials show a microstructure with CNTs covered by continuous TiO ₂ films of numerous small nanoparticles. After applying heat treatment on the hybrid nanomaterials at 1000 °C, only TiO ₂ nanoparticles adhere individually to the uncovered CNTs. Though all hybrid nanomaterials exhibit anatase TiO ₂, synchrotron X-ray absorption spectra investigations reveal that hybrid TiO ₂/CNTs exhibit different electronic properties as compared to those of pure TiO ₂ nanomaterials.