Studies and Preparation of TiO2 Photocatalysts Supported on Mesoporous Silica
Date Issued
2007
Date
2007
Author(s)
Lee, Yang-Chuan
DOI
zh-TW
Abstract
Abstract
This dissertatin studies the preparation and characterization of the photocatalyst in textile application and visible light photocatalyst. Heterogeneous photocatalysts have shown high efficiencies in the removal of pollutants including odors, micro- organisms, viruses, and volatile organic contaminants, commonly present in air and can resolve environment pollution problem. The photocatalyst was mixed into the textile fiber by either direct mixing or coating. However, the textile fiber itself was photo-degraded after exposure to sunlight because of the strong oxidizing power of the photocatalyst. In the present work, we attempt to prepare TiO2 particles encapsulated inside the pores of mesoporous silica materials by some preparation methods. The TiO2 supported catalysts were prepared by coprecipitation and on nano mesoporous silica(NMS) by consecutive grafting methods. Finally, we found the more useful method for TiO2 particles encapsulated inside the pores of mesoporous silica materials by one pot synthesis with the introduction of titania via the reverse microemulison and be incorporated into the final mesoporus silica product. In contrast to the coprecipitation method, which is quite facile the large TiO2 particles on the external surface of mesoporous SiO2 .
Moreover, we attempt to convert the TiO2 absorption onset from the ultraviolet to the visible region using mixed phase titania. The sun can provide an abundant source of photons; however, UV light accounts for only a small fraction (~5%) of the sun’s energy compared to the visible region (45%). Nanocrystalline TiO2 of high surface area (100-230 m2/g) and with various anatase/ rutile ratios was prepared by refluxing TiCl4 acid diluted solutions. The photodegradation of phenol in water was investigated using these mixed anatase/rutile phases TiO2 as the catalysts. When using 419 nm visible light as the light source, the mixed phase TiO2 revealed higher photocatalytic activities in phenol decomposition than that of Degussa P25. When TiO2 nanoparticles with mixed phases were supported on mesoporous silica material. Under 419 nm irradiation, the SBA-15 supported mixed phase TiO2 showed better photocatalytic activities than Degussa P25,too.
Subjects
介孔材料
二氧化矽
二氧化鈦
光觸媒
Mesoporous Silica
TiO2
Photocatalysts
Type
thesis
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