尿素作为添加剂低温制备高活性的TiO_2光催化剂

Low temperature synthesis of titanium dioxide with urea and their high photocatalytic activities

以钛酸丁酯为原料,尿素作为添加剂,在酸性水溶液中室温制备了稳定透明的TiO2水溶胶。经过300℃低温焙烧2 h,得到了由锐钛矿和金红石组成的TiO2混晶。用XRD、FT-IR对催化剂进行了表征。以甲基橙为降解对象研究了TiO2的光催化活性,实验结果显示所制备的TiO2具有比Degussa P25更高的催化活性,15m in后的降解率达到了78%(P25,58%)。考察了尿素添加量以及焙烧温度对TiO2催化性能的影响,当尿素与钛酸丁酯物质的量之比为3∶1,300℃下焙烧2 h为较适宜的催化剂制备条件。初步探讨了尿素作为添加剂在低温制备高活性TiO2过程中的作用。

Using tetrabutylorthotitanate as start materials and urea as the additive, titania sol was prepared in acidic water at room temperature. After calcining at 300 ℃ ,mixed - phase （ anatase and rutile） titanias were synthesized. The titanias were characterized by XRD and FT - IR. Photocatalytic activities were tested by the degradation of methyl orange （MO）. The results show that titanias as - prepared at low temperature have excellent photocatalytic activities ,even more than that of Degussa P25. MO was degraded up to 78% only illumination 15 min. while 58% for P25. The effects of the amount of urea and calcination temperature on photocatalytic activities were investigated. It is shown that titania calcined at 300 ℃ for 2 h has the best catalytic activity when the molar ratio of urea/tetrabutylo rthotitanate is up to 3. The possilble effect of urea in preparating high photocatalytic titania at low temperature was proposed.