高压辅助溶胶-凝胶法制备La掺杂TiO_(2)光催化剂及其可见光降解甲基橙研究

Method and Its Visible Light Degradation of Methyl Orange

根据溶胶-凝胶法和水热法制备TiO_(2)的优点和不足,本工作提出了一种高压辅助溶胶-凝胶法(简称HG法)可控地制备La掺杂TiO_(2)。通过该方法,可以高效制备锐钛矿相La掺杂TiO_(2),且制得样品纯度高,分散性好。通过控制La掺杂比例(0.05%、0.10%、0.15%、0.20%、0.25%,质量分数,下同),可以调控TiO_(2)禁带宽度变化(3.15~2.80 eV);其中,0.20%La掺杂TiO_(2)(0.20%La-TiO_(2))的禁带宽度可达2.80 eV。甲基橙(MO)光催化降解实验结果表明,0.20%La-TiO_(2)的光催化活性优异,其在可见光照射下160 min内对MO的降解率可达92%,是本征TiO_(2)的38.30倍;·O_(2)-是驱动0.20%La-TiO_(2)光催化降解MO的主要活性物质。本工作提出的高压辅助溶胶-凝胶法可为制备高活性TiO_(2)基光催化剂提供有益的方法及条件参考。

Based on the advantages and disadvantages of the sol-gel method and hydrothermal method in TiO_(2) preparation,a high pressure assisted sol-gel method was developed for the controllable preparation of La doped TiO_(2).Anatase La doped TiO_(2) with high purity and good dispersion was successfully prepared by this method.By the control of La doping ratios(0.05%,0.10%,0.15%,0.20%,0.25%),the band gap of La doped TiO_(2) can be adjusted in a range of 3.15-2.80 eV,and the 0.20%La doped TiO_(2)(0.20%La-TiO_(2))had a narrowest band gap of 2.80 eV.The photocatalytic experiments of methyl orange(MO)degradation showed that 0.20%La-TiO_(2) has higher photocatalytic activity than the others La doped TiO_(2) and the pristine TiO_(2).In the 0.20%La-TiO_(2)-based reaction system,the degradation rate of MO under visible light irradiation could reach 92%within 160 min.The photocatalytic activity of 0.20%La-TiO_(2) is 38.30 times higher than that of the pristine TiO_(2).The as-developed high pressure assisted sol-gel method in the present work could provide a useful method and condition reference for the preparation of highly active TiO_(2)-based photocatalysts.