Simple and fast annealing synthesis of titanium dioxide nanostructures

Titanium dioxide (TiO$_{2})$ has been intensively studied due to its useful applications such as dye-sensitized solar cells and electrodes in lithium ion batteries. In this study diverse TiO$_{2}$ nanostructures were synthesized by a simplified synthetic method. Since it does not require a high reaction temperature or complicated processes it can be useful for producing a large quantity of TiO$_{2}$ nanomaterials at very low temperatures. Crucial synthesis conditions such as eutectic catalyst (copper), growth temperatures, and annealing time were systematically investigated. Only 30 minutes annealing at 850 $^{\circ}$C was enough to produce densely-packed $\sim $ 10 $\mu $m long nanowires ($\sim $ 100 nm diameter), and a longer reaction time changed morphology from wires to belts. The nanostructures were identified to be rutile structure with the 110 growth direction by x-ray and electron diffraction. Our simple but effective method can be utilized for other metal oxide nanowires, especially with materials of a high melting temperature.