纳米二氧化钛纤维的制备及其光催化活性

PREPARATION OF NANO-TITANIA FIBER AND ITS PHOTOCATALYTIC ACTIVITY

以钛酸丁酯为钛源,用溶胶乳化凝胶技术合成了纳米TiO2粉末,将其置入碱溶液中进行回流处理得到了纳米TiO2纤维。用X射线衍射和透射电镜对纳米TiO2的晶型和表面形貌进行表征。结果表明:当氢氧化钠溶液的浓度为10mol/L时,所制备的纳米TiO2纤维直径为10～15nm,纤维长径比为20～25。TiO2纤维在750℃热处理后发生由锐钛矿相向金红石相的转变。光催化降解亚甲基蓝的实验显示:未经热处理的TiO2纤维的光催化活性比纳米TiO2粉末的差,而经500℃热处理后的TiO2纤维光催化活性最强,在紫外光照射4h后,亚甲基蓝降解率达92%。当热处理温度进一步升高后,TiO2纤维光催化活性反而降低。

Using tetrabutyltitanate as titanium source, nano-TiO2 powders were synthesized by the sol-emulsion-gel method. The titania fibers were prepared by a refluxing process using the above nano-TiO2 powders as the materials immerging into the NaOH solution. The crystal phase and morphology of nano-TiO2 were characterized by X-ray diffraction and transmission electron microscope. The results show that the diameter of TiO2 fiber is 10-15 nm and the ratio of length to diameter is 20-25. The phase transition temperature of TiO2 fiber from anatase to rutile is 750℃. The experiment of photocatalytic degradation methylene blue indicated that the photocatalytic activity of titania fiber without heat treatment was lower than that of nano-TiO2 powders, and it was highest after treated at 500℃. The degradation rate of methylene blue is 92% after irradiated 4 h with ultraviolet light. With the further increasing the heat treatment temperature, the photocatalytic activity of titania fiber decreased gradually.