(257i) Hydrothermal Synthesis of TiO2 Nanomaterials with Ethylenediamine

TiO₂ nanomaterials were synthesized by hydrothermal method under basic conditions using ethylenediamine (EDA) and the characterization of the resulting products was performed. In this study, the effect of EDA concentration, synthesis temperature, and difference in Ti source on crystallinity, crystalline structure, morphology and photocatalytic activity of the resulting TiO₂ was examined. Distilled water with low concentration of EDA was used as medium and titanium tetraisopropoxide (TTIP) or tetra-n-butyltitanate (TNBT) was used as Ti source. The results showed that distilled water with very low concentration of EDA (0.05 and 0.45 mol%) resulted in almost pure anatase TiO₂ with very high crystallinity at 180°C for both Ti sources of TTIP and TNBT. Less than or more than the above concentration of EDA resulted in partially amorphous pure anatase or mixed phase of anatase and brookite. With the increase of EDA concentration, ratio of brookite phase to anatase phase was increased and morphology was changed from sphere to rod like structure. Below 180°C, only amorphous phase TiO₂ was obtained. Difference in Ti source made little difference in most of the properties such as crystalline phase, crystallinity. Decomposition experiment of 2,4-Dinitrophenol (DNP) under UV irradiation demonstrated that photocatalytic activity of the resulting TiO₂ was much higher that P-25 which was known as high activity TiO₂.