二氧化鈦是一種能將有害物質分解為二氧化碳和水的光觸媒之一，在本研究中以溶凝膠法製備二氧化鈦凝膠，本研究中以四氯化鈦做為前驅物，過氧化氫做為塑解劑，在95 °C度高溫下將氫氧化鈦水溶液轉換成二氧化鈦凝膠。本研究之目的最主要在於將二氧化鈦改質，以提高二氧化鈦之穩定性以及加強二氧化鈦在可見光範圍之光催化效率。加入銀可以使二氧化鈦溶膠有更好的抗菌能力，並且有效地降低顆粒凝聚現象、達到更好的穩定度。 本研究透過XRD和HRTEM的晶格距離可得到樣品所對應二氧化鈦的銳鈦礦相。DLS和HRTEM的結果呈現改值後的二氧化鈦的粒徑較未改質前小，此外也可由ζ電位(Zeta potential)的大小確認維生素C有增強二氧化鈦溶膠的穩定度。 本研究使用亞甲基藍染料為維生素C-二氧化鈦溶膠的光降解活性做測試 ，經由UV-Vis分析可得到:在紫外光或可見光的照射下，二氧化鈦和銀的比例為2 wt. %時的光催化效果是最好的。 ;Titanium dioxide, also called titania, is a kind of photocatalyst that can degrade harmful materials 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. The purpose of this study was to apply sol-gel method to prepare silver-modified TiO2 for enhancement of sol stability, TiO2 particle size distribution, and improvement of photocatalytic activity under UV light and visible light irradiation. The presence of silver can lead to high antibacterial capability. The photocatalysts were characterized by XRD, DLS, SEM, TEM, HRTEM, FTIR, and UV-Vis spectroscopy. We could confirm that our titanium sols are anatase by XRD and HRTEM. And by DLS and HRTEM, we could figure out that the diameters of modified TiO2 are smaller than those of pure TiO2. The Zeta potential of the modified TiO2 is higher than that of pure ones. As a result, the addition of silver could improve the photocatalytic activity and prevented the particles from agglomeration; besides, the sols remained stable and did not precipitates after storage for over a year. It was observed that the optimum Ag to TiO2 ratio was 1 wt%, and the sample showed higher photocatalytic activity under both UV and visible light irradiation.
