Characterization of a TiO₂/Multi-Wall Carbon Nanotube Core-Shell Nanocomposite Synthesized by a Hydrothermal Method

TiO₂ is a significant n-type semiconducting material because of its superior electric and photocatalytic properties. Although this material has been extensively studied as a semiconductor electrode for dye-sensitized solar cells for its inherent bandgap and its excellent electrical and chemical properties, the photoelectric efficiency is nevertheless lower than that of the Si-based solar cells, which is generally reported as 13-27%. On the other hand, various carbon structures have been studied to increase the overall charge transport efficiency by reducing the charge transport resistance in the cell while having high electric conductivity. These results are expected to improve the photoelectric conversion efficiency when applied to dye-sensitized solar cells. We fabricated a TiO₂/multi-wall carbon nanotube (MWCNT) core-shell structure by a hydrothermal method. The TiO₂ anatase phase in the TiO₂/MWCNT core-shell structure was confirmed by X-ray diffraction (XRD). The core-shell nanostructure with a diameter of 127 nm to 211 nm was observed by field emission scanning electron microscope (FE-SEM). The morphology of the TiO₂/MWCNT core-shell nanocomposite was also analyzed by transmission electron microscope (TEM). The Fourier-Transform Infrared Spectrometer (FT-IR) and Brunauer Emmett and Teller (BET) method were used to observe the chemical bonding and specific surface area of the TiO₂/MWCNT core-shell nanocomposite, respectively. The TiO₂/MWCNT core-shell composites had a larger specific surface area of 92.00 m²/g, a larger pore volume of 0.33 cm³/g, and a larger pore size of 65.21 nm than commercial TiO₂ nanoparticles (P25). The TiO₂/MWCNT core-shell structure may provide a high-speed path for photoelectrons to pass quickly and will be useful for various applications, such as solar cells and photocatalysts.