| Summary: | 碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 106 === P/Si-TiO2 thick films with high photocatalytic activities firmly adhered on FTO glass substrates were prepared using the sol-gel method, spin-coating and bar-coating techniques. The TiO2 thin film coated on the FTO glass substrate, as a base layer for P/Si-TiO2 thick film, was formed via a spin-coating technique. The slurry containing the gel-derived P/Si-TiO2 nanoparticles was then bar-coated on the TiO2 base layer, followed by calcining at 550 °C to form the photocatalytic thick film on the FTO glass substrates. The specimens were characterized using X-ray diffractometer, ultraviolet-visible spectro- photometer, scanning electron microscope, stylus profiler and adhesion test (ASTM D 3359-95). By photocatalytic degradation of methylene blue (MB), the photocatalytic activities of the films were measured and represented using the corresponding characteristic time constant (τ). Smaller τ is, the higher is the photocatalytic ability of the film. The P/Si-TiO2 thick film, prepared from the slurry containing 20 wt.% of the calcined P/Si-TiO2 powder at 800 °C, gave the superior performance in photocatalysis; this thick film had τ=3.59 hours and decomposed about 81 mole% of MB in the water after 6 h, under irradiation 365-nm UV light. For the sake of comparison, the TiO2 thin film decomposed 29 mol% MB in water (τ= 18 hours) under the same conditions. Kinetic analysis showed that the photocatalytic abilities of P/Si-TiO2 thick films are directly proportional to the photocatalytic area (NS; N: number of specimens, S: area), and have a power relationship with light intensity (I). By experimental data fitting, it was found that τ = [(0.052N+0.002)I0.338]-1, which can well predict the characteristic time constant of the P/Si-TiO2 thick films at different operation conditions.
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