Investigation Of The Growth Of Crystallized TiO₂Nanoparticles On Flexible Organic Nanofibers Membrane&Its CO₂Photoreduction Application

CO2photoreduction system is known as artificial photosynthesis process because it uses solar energy, carbon dioxide and water to synthesize useful hydrocarbon fuels. During the conversion of inorganic carbon which contributed by carbon dioxide to organic hydrocarbon fuel, semiconductor TiO2plays an important role to undergo a series of redox reaction. In this redox reaction, CO2is reduced by accepting hydrogen atoms while water is oxidized by losing hydrogen atoms through a series of simultaneous or consecutive electronation-protonation steps. Therefore, the photogenerated electron-hole pair needs to be separated into the conduction band and valence band respectively in the semiconductor. Then CO2molecules react with the photogenerated electron in conduction band and water molecules react with the photogenerated hole in the valence band of TiO2. In order to prevent the photogenerated electron-hole pair recombination in TiO2, various methods had been proposed as follows:●Sensitizing the surface of TiO2semiconductor with higher electronegativity fluorine to reduce the recombination of photogenerated electron-hole pairs.●Depositing copper nanoparticles on TiO2to induce local surface plasmons effect in order to enhance CO2photoreduction rate.In this thesis, a combination of electrospinning followed by hydrothermal treatment was used to fabricate higher complexity materials with specific characteristics as follow:●Producing flexible, large surface area and porous membrane.●The organic electrospun nanofiber membrane can induce the growth of crystallized TiO2in hydrothermal environment.●Doping of TiO2nanoparticles which grown on electrospun nanofiber, enhances the optical absorption ability in visible light region.The CO2photoreduction ability of fabricated TiO2on electrospun membranes were subsequently analyzed by using photoluminescence and X-ray photoelectron spectroscope was used to analyze the chemical structures of fabricated TiO2with organic electrospun nanofibers. While the CO2photoreduction testing was carried out in a home-made reactor under UVA light source for TiO2samples and under simulated sunlight for doped-TiO2sample.