镧掺杂混晶结构TiO_2纳米粉体的制备及其光催化性能

Synthesis and Photocatalytic Performance of La-doped Mixed Crystal TiO_2 Nanopowder

以钛酸四丁酯为Ti源,采用溶胶-凝胶自蔓燃法制备了镧掺杂的La-TiO2(简写为LT)纳米粉体。利用X射线粉末衍射(XRD)、红外光谱(FIIR)、透射电子显微镜(TEM)等对掺杂型TiO2粉体的晶型结构与颗粒尺寸等进行表征。利用紫外-可见光吸收光谱(UV-vis)研究了H2O2改性、镧掺杂量以及混晶结构对TiO2纳米粉体降解甲基橙的影响。结果表明:镧掺杂混晶TiO2粉体的光催化活性明显优于未掺杂的锐钛矿TiO2粉体。当La3+掺杂量为0.5%,合成温度为475℃(金红石相含量为26.0%)时,得到的TiO2粉体光催化活性最好。H2O2的加入有助于TiO2光催化剂表面的电子-空穴对生成,提高光催化剂对甲基橙的降解率,当H2O2浓度为6%时,光照3 h后,降解率达到了91.97%。

Using tetrabutyl titanate as the titanium source,nanopowders of TiO2doped with La（LT） were synthesized by sol-gel combustion method.The crystal structure and particle size of doped TiO2powders were characterized by X-ray powder diffraction（XRD）,Infrared spectroscopy（IR） and transmission electron microscope（TEM）.The effects of H2O2addition,lanthanum content,and mixed crystal structure for TiO2on the photocatalytic degradation of methyl orange under the sunlight were investigated by Ultraviolet-visible absorption spectra（UV-vis）.The experimental results showed that the anatase/rutile mixed phase TiO2with La-doped exhibited higher photocatalytic activities than un-doped anatase phase TiO2,The supreme photocatalytic activity of TiO2powder,which was composed of 74% anatase and26% rutile,were obtained for the Lanthanum content of 0.5% and at synthesized temperature of 475 ℃.The addition of H2O2increased the number of electron-hole pairs on the surface of the TiO2catalyst,and then improved the photo-degradation rate of methyl orange.When the concentration of H2O2was 6%,the degradation rate reached 91.97% after 3 h solar light irradiation.