二氧化鈦是一種具半導體性質的觸媒，可利用低能量之紫外光照射進行污染物光催化分解反應，本研究以添加劑嘗試減小二氧化鈦的能隙，改善二氧化鈦的光吸收特性，並將其塗佈於玻璃管表面，利用紫外光的照射來處理空氣中的苯及甲苯。 本研究是以溶膠凝膠法合成二氧化鈦，在水解反應中添加Cr＋3、Fe＋3、V＋4等過渡元素金屬離子，所得到的改質之二氧化鈦膠，其所測得微結晶粒子皆在10 nm 以下，在經3∼4個月的靜置，也不會沈澱。以3：7水及乙醇重量比的鍍膜液用浸漬覆膜的方法鍍於玻璃管表面上，在空氣及空氣水汽共同存在下進行苯及甲苯的光催化反應。我們發現不管有無添加過渡元素金屬離子在有空氣水汽共同存在下二氧化鈦的催化效果都比只有在空氣下的催化效率好，且添加少量過渡元素金屬離子的二氧化鈦之苯及甲苯光催化效率比添加多量過渡元素金屬離子的光催化效率好但其催化效率並不如二氧化鈦來得好。另外添加過渡元素金屬離子確實可增加二氧化鈦在可見光範圍的吸收。 Titanium oxide is a photocatalyst with semiconducting properties. It can decompose the pollutants by irradiation of low energy UV light . This report attempted to decrease the bandgap of TiO2, and to improve the optical absorption properties in visible region. The thin film of modified titanium oxide was coated on glass tubes , and tested for photo-decomposition of benzene and toluene under air with and without additional water vapor by irradiation of UV light (350 nm). Titanium oxide gels were synthesized by sol-gel method . The modified TiO2 gels were obtained by adding the transition metal ions such as Cr+3 , Fe+3 , V+4 in the hydrolysis reaction of TiO2. The diameters of the modified as synthesized TiO2 particles are below 10 nm and the suspensions are stable after 3~4 months. The gels were coated on glass tubes and tested for photo-decomposition of benzene and toluene.The rates of photo-decompositions under air with and additional water vapor are higher than those without additional water vapor. The rates of photo-decomposition over titanium oxide doped with less amount of transition metal ions are better than titanium oxide doped with large amount of transition metal ions.The rate of photo-decomposition over titanium oxide doping with transition metal ions is less than titanium oxide without doping under the irradiation of UV light (350 nm).Doping transition metal ions such as Cr+3 , Fe+3 , V+4 in TiO2 did increase the absorption of the visible region.
