水热法制备具有高光催化活性的镧掺杂二氧化钛纳米晶(英文)

La-doped titania nanocrystals with superior photocatalytic activity prepared by hydrothermal method

采用水热法合成钛酸钾(K2Ti8O17)纳米棒,并将它作为前驱体水热转晶合成TiO2纳米晶,同时通过在水热体系中引入稀土元素La3+实现对TiO2的La掺杂.考察了不同条件下钛酸盐向TiO2的转晶过程,发现水热溶液的pH值、温度以及预处理步骤对转晶过程有很大的影响.利用X射线衍射以及透射电子显微镜对样品的晶相和形貌进行了表征.利用电感耦合等离子体原子发射光谱测量了所合成的La掺杂TiO2样品中的La含量.通过在紫外光下降解甲基橙(MO,10mg/L)测试了La掺杂TiO2样品的光催化性能.结果表明La掺杂后TiO2的光催化活性大大提高.在0.15mol/LLa3+浓度下180°C水热合成的La掺杂TiO2样品显示了最佳的光催化活性.其对MO的光催化降解反应常数高达0.11min1,大约是空白TiO2样品的9.20倍,P25TiO2的3.69倍.

Potassium titanate(KTO) nanobars were synthesized by a hydrothermal method and used as a precursor to synthesize TiO 2 nanocrystals.La doping of the TiO 2 nanocrystals was achieved by introducing La3+ into the hydrothermal media.The hydrothermal transition of KTO to TiO 2 was investigated under various conditions,finding that the pH of the hydrothermal media,the temperature,and the pre-treating procedure play important roles in the phase transition.X-ray diffraction and transmission electron microscopy were used to characterize the crystal phase and morphology of the samples and the transition process of the hydrothermal reaction.The content of La3+ in the samples was measured by inductively coupled plasma atomic emission spectroscopy.The photocatalytic activity of the La-doped TiO 2(LaT) was measured under UV light with the degradation of methyl orange(MO,10 mg/L).The results showed that the photocatalytic activity of TiO 2 was enhanced remarkably by La-doping.LaT hydrothermally prepared with 0.15 mol/L La3+ at under 180 °C showed the optimal reaction constant of 0.11 min-1 for the degradation of MO,about 9.20 and 3.69 times than those of bare TiO 2 and P25,respectively.