溶胶-凝胶法制备Eu^(3+)-Ce^(3+)共掺杂TiO_2及光催化性能

Photocatalytic Properties of Eu^(3+)-Ce^(3+) Co-doped TiO_2 Nanoparticles by Sol-gel Method

采用溶胶-凝胶法制备了Eu^(3+)-Ce^(3+)共掺杂TiO_2纳米粉体,以亚甲基蓝溶液为目标降解物、用正交试验方法考察了内部因素和外部因素对掺杂样品的光吸收和光催化性能的影响,同时采用XRD、FE-SEM、UV-Vis吸收谱等表征了样品结构与性能。结果表明,最佳的实验方案是热处理温度为550℃、Ce^(3+)的掺杂量为0.02mol%、Eu^(3+)的掺杂量为0.2mol%,最佳的外部环境是共掺杂TiO_2纳米粉体光催化剂加入量为0.15 g/50 mL、亚甲基蓝溶液的初始pH值及浓度分别为6.5和10 mg/L。样品的晶粒尺寸在20 nm左右,共掺样品的光催化率明显比单掺和未掺样品的高,且吸收边向可见光红移了53nm左右。共掺样品对亚甲基蓝降解反应符合一级动力学模式。共掺样品光催化率的提高归因于Eu^(3+)和Ce^(3+)的协同作用,一方面增加有效的空穴电子数;另一方面可使样品吸收更低能量的波长而被激发。

Eu3＋-Ce3＋ co-doped Nano-TiO2 was prepared by sol-gel method and the photocatalytic activity under ultra-violet light was evaluated by photocatalytic degradation of methyl blue. The microstructure and performance were characterized by testing techniques such as XRD, FE-SEM, and UV-Vis. The influence of internal and external factors on the photoabsorption and photocatalytic properties of the co- doped samples was tested by orthogonal experiments. The results show the optimal conditions are as follows： the doping amounts of Ce3＋ and En3＋ are 0.02mo1% and 0.02mo1% respectively; the heating temperature is 550 ^（2; the average size is 20nm; the optimal addition amount is 0.15 g/50 mL, the initial concentration is 10mg/L and the pH value is 6.5. The resulted photocatalysis rate of the co-doped samples was better than that of the samples without doping. The co-doped samples cause the red-shift （53 nm） of the optical absorption edge and increase the UV-Vis light absorption. The methyl blue degradation of the co-doped photocatalyst coincides with the first order dynamic equation. The reason for the photocatalysis rate rise was the increase of effective electron and hole, which also excited the sample by helping it absorb lower energy light.