| Summary: | 碩士 === 國立臺灣科技大學 === 高分子系 === 98 === Vanadium dioxide (VO2) is regarded as a “green” material, which could be applied on windows of a building to save energy due to the thermally-reversible phase transition property. In addition, titanium dioxide (TiO2) exhibiting hydrophilic and photocatalytic properties is known as a self-cleaning material when applied on the window of a building. We attempted to synthesize TiO2-VO2 hybrid materials to include both functions of saving energy and self-cleaning in one materials.
Ti(OiPr)4, VO(OiPr)3 and glacial acetic acid containing various ratios were used to mix with PVP、HTAB and 2-propanol to be precursors. Thermogravimetric analysis (TGA) is used to observe the pyrolysis temperature of precursors for each stage. We confirmed the functional groups of precursor by fourier transform infrared (FT-IR) spectrometer. Sequentially, precursors are sintered at 550℃, obtaining from TGA, for one hour to obtain Ti1-xVxO2 materials. The Ti1-xVxO2 materials demonstrated various nanostructures under scanning electron microscope (SEM) observation. These Ti1-xVxO2 materials were defined by energy sispersive spectrometer (EDS) analysis. The results illustrate that Ti1-V2-PVP composite powder, Ti1-V1-PVP composite powder and Ti2-V1-PVP composite powder demonstrated echinus-like, hexagonal column and gear-like configurations. X-ray diffraction (XRD) analysis indicated that Ti1-V1-PVP composite powder was composd by several lattice structures including TiVO4, TiO2(Anatase), V2O5 and VO2. While Ti1-V2-PVP composite powder and Ti2-V1-PVP composite powder demonstrated pure lattice of TiO2(Anatase) and VO2, respectively. The phase transition temperatures of Ti1-V2-PVP composite powder, Ti1-V1-PVP composite powder and Ti2-V1-PVP composite powder were 58.2℃, 77.3℃ and 59.1℃ from differential scanning calorimetry (DSC) measurement, respectively. The decomposition efficiency of Methylene blue for Ti1-V2-PVP composite powder, Ti1-V1-PVP composite powder ,and Ti2-V1-PVP composite powder approach to 79.6%, 80.5% and 99.6% under UV exposure. We found a novel material including two advantages of TiO2 and VO2 in our work.
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