低量Gd~3+掺杂TiO_2粉体的制备及催化活性

利用溶胶-凝胶法在700℃制备了纯的和不同Gd3+掺杂量的TiO2纳米粉体,并用XRD技术对样品进行了表征。研究了Gd3+掺杂量对样品相结构、晶粒尺寸和光催化降解亚甲基蓝的活性的影响,利用相结构与纳米TiO2光催化活性关系探讨了Gd3+掺杂对纳米TiO2的光催化活性。结果表明,与纯TiO2相比,适量掺杂Gd3+可以显著提高其光催化活性。当Gd3+掺杂量为0.2%(质量),TiO2复合纳米粉体的光催化活性最佳,降解率为86%,其金红石相含量为15.4%,平均晶粒粒径为15nm;Gd3+掺杂强烈地抑制TiO2由锐钛矿相向金红石相的转变、减小晶粒尺寸和晶格膨胀程度这三方面均有利于提高光催化活性。

Preparation and Photocatalytic Activities of Low Amount Gd~(3+)-doping TiO_2 Composite Nano-powders

Pure and Gd3+-doped TiO2 nano-powders with amounts of Gd3+-doped were prepared at 700℃ for 1h by sol-gel method using Ti(OC4H9)4 as precursors and characterized with XRD.Effects of the amount of Gd3+-doping on the photocatalytic activity for photocatalytic degradation of methylene blue in solution,phase structure and crystallite size of nanopowders were investigated.Mechanism of the effects of Gd3+-doping on photocatalytic activity of TiO2 nano-powders was discussed in relationship between the crystal structure and its photocatalytic activity.Results showed that 0.2% Gd3+-doping can significantly enhance the photocatalytic activity of TiO2 nano-powders,with mass percent of rutile phase 15.4%,degradation rate 86% and crystalline sizes about 15nm.The presence of Gd3+-doping in TiO2 can inhibit the phase transformation from anatase to rutile,suppress the growth of TiO2 grains and crystallatticeexpandin,which resulted in increase in the photoactivity.