| Description |
Titanium dioxide (TiO2) has been used in a wide variety of applications mainly because of its physical and chemical properties. For example, it has a typical band-gap of 3.2 eV, and as such it can absorb UV light and consequently be used as a component in sunscreen or as a photocatalyst (under UV illumination) for degradation of organic pollutants. In addition, its’ morphology can be altered (depending on the application) to structures such as spheres, tubes, fibers, rods, etc. usually on length scales ranging from nano- to micron sizes. Specifically, the synthesis of nanorods of TiO2 has recently been shown a large interest as they are known to have an advantage in charge transport and hence have been cited for use in photovoltaic devices such as dye sensitized solar cells (DSSC).
Numerous methods have been reported to synthesize TiO2 nanorods including sol-gel and hydrothermal methods. In these methods titanium alkoxides or titanium tetra halides are used as titanium sources which are highly moisture sensitive and it is hard to control their hydrolysis resulting heterogeneity in the reaction mixture. In those processes, the byproducts are also formed which are not eco-friendly and need to be removed from the reaction mixture. In case of template synthesis, the template needs to be selectively removed after the preparation. To prepare the precursors of TiO2 nanorods with total exclusion of moisture, we report here a novel method which consists of one-step, low temperature (100-200 °C), facile and a low-cost solvothermal route. A unique TiO2 precursor is first obtained having a rod like structure and it can then subsequently be converted to anatase and rutile phases through calcination without changing the overall morphology. The as synthesized and calcined products were characterized by Transmission Electron Microscope, X-Ray Diffraction and Thermo-Gravimetric Analysis and the anatase phases were applied in DSSC. A unique liquid precursor has been also synthesized and characterized through thermal and NMR analysis.
We have also tried to change the bandgap of the TiO2 from UV range to visible range through the single (nitrogen) and dual (nitrogen and tungsten) doping to use it as a photocatalyst under the visible light illumination.
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