二氧化鈦是一種可以將有害的有機化合物降解成水和二氧化碳的光催化劑。 在本研究中，二氧化鈦是溶膠凝膠法(sol-gel method)製備而成的。製備過程中以四氯化鈦為前驅物，過氧化氫為膠溶劑，在95℃下從氫氧化鈦水溶液轉化成具有二氧化鈦納米粒子的凝膠。加入銀是為了提高二氧化鈦的穩定性、可見光範圍的效率和抗菌能力。最後將二氧化矽加入到銀-二氧化鈦溶膠中來降低顆粒的凝聚現象與提高溶膠的穩定性和透射率。本研究的目的是加入銀將二氧化鈦二氧化矽溶膠改質，用於提高溶膠穩定性、增加在紫外光和可見光照射下光催化活性，以及高抗菌力。XRD和HRTEM證實可得到樣品的晶格距離所對應的是二氧化鈦的銳鈦礦相。通過DLS和HRTEM測量粒徑。在紫外光和可見光照射下，二氧化鈦-二氧化矽和銀-二氧化鈦-二氧化矽的溶膠與薄膜對亞甲基藍皆有光催化效果。最後結果顯示銀-二氧化鈦-二氧化矽的光催化效果高於二氧化鈦-二氧化矽。經UV-Vis分析添加銀可以提高光催化活性。此外，存放一年後溶膠依舊穩定且酸鹼度依然維持中性，溶膠皆沒有變質分解。在紫外光和可見光照射下最佳的二氧化矽/二氧化鈦/銀莫耳比為5/1/0.02，皆表現出較高的光催化活性。抗菌試驗顯示經UVA光照射3小時後，銀-二氧化鈦-二氧化矽具有良好的抗菌能力，抗菌率高達99.9％以上。;TiO2 is a photocatalys that can degrade harmful organic compounds into H2O and CO2. In this study, TiO2 sol was prepared by sol-gel method using TiCl4 as precursor and H2O2 as peptizing agent in order to induce the formation of TiO2 nanoparticles that converted from Ti(OH)4 under 95°C. In order to find an efficient way to improve the activity of photocatalyst and antibacterial property, silver was added. SiO2 was then added in the silver-titanium dioxide sol to improve the transmittance of the sol. The purpose of this study was to apply a sol-gel method to prepare silver modified SiO2/TiO2 to enhance stability of sol, TiO2 particle size distribution, and improve photocatalytic activity under UV light and visible light irradiation. The presence of silver lead to high antibacterial capability. The nanoparticles were characterized by X–ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR–TEM), scanning electron microscope (SEM), X–ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and UV-Vis spectroscopy. Titanium dioxide sols were anatase as confirmed by XRD and HRTEM. The particle size of the smaple was measured by DLS and HRTEM. Both the sols and the films of titania-silica and silver-titania-silica were active for methylene blue destruction under UV light and visible light irradiation. The results showed that the quantum efficiency of silver-titania-silica was higher than that of titania-silica. The addition of silver could improve the phtocatalytic activity. In addition, the sols remained neutral, stable and did not separate after storage for over a year. The optimum SiO2/TiO2/silver molar ratios were 5/1/0.02, and it showed high photocatalytic activities under both of UV light and visible light irradiation. From antibacteria test, it showed that after irradiation by UVA light for 3 hours, the silver-titania-silica had a high antibacterial ability, and the antibacteria rate reached over 99.9%.
