La~(3+)掺杂TiO_2粉体的化学沉淀法制备条件优化

采用化学沉淀法制备La~(3+)掺杂TiO_2粉体,并用正交实验方法对制备工艺进行优化,通过SEM、XRD、XPS和UV-Vis对TiO_2粉体的形貌、结构、光吸收性能进行了表征。结果表明:煅烧温度和La~(3+)掺杂量对TiO_2粉体光吸收性能具有显著影响;不同煅烧温度得到的La~(3+)掺杂TiO_2均以锐钛矿结构为主;升高煅烧温度可以增强La~(3+)掺杂TiO_2在紫外光波段的吸光强度;La~(3+)掺杂可以改善TiO_2粉体的团聚,减小TiO_2的禁带宽度,同时导致TiO_2表面吸附一定数量的羟基。最优的制备条件为:煅烧温度800℃,La~(3+)掺杂量0.6%(摩尔分数),反应温度为90℃,反应液pH值为8,此条件下获得的TiO_2粉体可见光性能最优。

Preparation Optimization of La3+ Doped TiO2 Powder by Chemical Precipitation

La3+ doped TiO2 powder was prepared by chemical precipitation and the technique was optimized by an orthogonal experiment. The morphology, structure and light absorption properties of TiO2 powders were characterized by SEM, XRD, XPS and UV-Vis. The results show that the effect of the calcinating temperature and the amount of La3+ on optical absorption properties of TiO2 is significant. The main crystal structure of La3+ doped TiO2 powder at different calcinating temperatures is anatase. Higher calcinating temperature can enhance the absorption intensity of La3+ doped TiO2 in the UV band. Doping La3+ can improve agglomeration of TiO2 powder and narrow the band gap of TiO2. In addition, a certain amount of hydroxyls are also adsorbed on the surface of TiO2 due to La3+ doping. The optimal preparation conditions of La3+ doped TiO2 powder are as follows: the calcinating temperature 800 °C, the amount of La3+ 0. 6 mol%, the solution temperature 90°C, and the pH value 8.0. TiO2 powder prepared under the above conditions has the optimal visible light property.