混晶结构纳米TiO_2粉的光催化活性

The photocatalytic activity of nano-TiO_2 powder with mixed crystal structure

以钛酸四丁酯为钛源制备混晶结构纳米TiO2粉,研究了纳米TiO2的光催化活性与颗粒晶相结构之间的关系．结果表明,当金红石相的质量分数少于18．53％,光催化活性随着金红石相的增多而降低;当金红石相的质量分数为18．53％-28．2％时,随着金红石相的增多,光催化活性逐渐增强,在28．2％附近具有最高的光催化活性,与纯锐钛矿结构纳米TiO2粉的光催化活性相当;金红石相含量继续增加,则光催化活性逐渐降低．适量金红石相的存在有利于锐钛矿相中的电荷分离,使光催化活性提高．

The nano-TiO2 powders of mixed crystal structure were prepared and charactered. The relationship between the crystal structure and its photocatalytic activity was investigated. The results show that photocatalytic activity of TiO2 was reduced firstly, when the mass percent of rutile phase was less 18.53%. When the mass fraction of rutile phase was in the range from 18.53% to 28.2%, the activity of TiO2 was promoted. The TiO2 powder contained 28.2% rutile phase was most active and degraded 97% Rhodamine B in 60 min. When the mass percent of rutile phase exceeded 28.2%, the catalytic activity reduced renewedly. The existence of rutile phase in definite quantity favors the charge seperation and promote the photocatalytic activity.