Abstract:
The primary goal of this thesis is to synthesize titanium dioxide nanorods using a continuous flow microreactor. Titania powder, one of the most important particulate materials is used for many purposes owing to its excellent optical properties of a high refractive index leading to high hiding power and whiteness of titania paint, high chemical stability, and relatively low production cost. Particularly, one-dimensional inorganic nanostructures (rods, wires and tubes) of TiO₂ attract both relevant theoretical and technological interest, because they reveal a wide range of electrical and optical properties that depend on both size and shape.
In our research, the growth of anatase TiO₂ nanorods was carefully controlled at low reaction temperature (around 100 °C) with oleic acid as a surfactant preventing hydrolysis of titania nuclei in undesired sites. Hinder hydrolysis of titanium alkoxide has been engaged and manipulated by means of a strategy that relies on the chemical modification of the titania precursor (Titanium tetraisopropoxide and Oleic acid) by the carboxylic acid, and on the use of suitable catalysts (trimethylamino-N-oxide dehydrate, TMAO) to promote crystallization in a continues flow microreactor. The X-ray diffraction and raman spectroscopy analysis show that TiO₂ produced from the microreactor matched with the products from the batch synthesis. Scanning Transmission electron Microscope (TEM) and High Resolution TEM images show that TiO₂ nanoparticles were rod shape, and Fourier transform of the HRTEM image indicates that mineral form of TiO₂ corresponds to the standard TiO2 anatase diffraction pattern. Thermal Gravimetric Analysis indicates that TiO₂ nanorods produced from the microreactor have more ligands attached to their surface than nanorods made by the batch reactor. The continuous flow microreactor can produce TiO₂ nanorods much faster (about 40 to 50 min of residence time) than a batch reactor (with reaction time around 24 hr), and the quality of the TiO₂ nanorods from the microreactor is as good as the nanorods from the conventional batch reactor.
