| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 98 === The main purpose of this work is to fabricate a transparent visible-light-active nitrogen-doped TiO2/SiO2 self-cleaning surfaces. All-nanoparticle thin film coatings on glass substrates by electrostatic layer-by-layer (ELbL) assembly of 7 nm TiO2 and 22 nm SiO2 nanoparticles were performed. Followed by periodic calcination process after every 30 bilayers, then calcine the coatings under ammonia gas flow with different temperature and number of bilayer, multibilayer nitrogen-doped nanoparticulate thin films (TiO2-δNδ/SiO2 )X with x=1-120 can be fabricated and to determine effects of N-doping temperature and thin film thickness under visible light illumination.
Antireflective property was exhibited by all of the nanoparticulate thin films fabricated as revealed by UV-vis transmittance spectra. In addition, average refractive indices of the nanoparticle thin films about 1.31±0.05 and linear growth behavior nearly 20.03±0.07 nm for a bilayer of the multilayers were determined using ellipsometry and scanning electron microscopy. According the result of experiment, N-doped TiO2 thin film can be fabricated by different calcination temperature under NH3 gas flow and extend absorbance wavelength from UV light to visible light. Beside, there is an optimum calcination temperature condition (500℃/NH3) to show the best photocatalytic activity which is evaluated by the degradation of methylene blue under visible light illumination. This suggests that the isolated narrow band formed above the valence band is responsible for the visible light response in the present N-doped TiO2 but nitrogen doping is likely to be accompanied by oxygen vacancy formation. Furthermore, photocatalytic degradation of methylene blue by the nanoparticle thin films with different number of bilayers under visible light illumination showed the same self-cleaning property.
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