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研究了用一步水热法制备的掺镧钛酸铋(Bi3.25La0.75Ti3O12, BLT)纳米线的光学和可见光催化性能, 并对其晶体结构和微观结构用X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等手段进行了表征. 结果表明, 制备的纳米线为纯相的Bi3.25La0.75Ti3O12, 平均直径约为 25nm. 室温光致发(PL)光谱显示BLT 纳米线在 433 和 565nm 附近有较强的发射峰, 分别对应激子发射和表面缺陷发光. 紫外-可见漫反射光谱(UV-Vis DRS)表明 BLT 样品的带隙能约为 2.07 eV. 利用可见光(λ>420nm)照射下的甲基橙(MO)降解实验评价了BLT样品的光催化性能. 结果表明, BLT的光催化活性比商用TiO2催化剂P25、掺氮TiO2和纯相钛酸铋(Bi4Ti3O12, BIT)高得多. BLT光催化剂具有更高催化活性的原因是 La3+离子的掺杂拓展了BIT对可见光的吸收范围, 同时抑制了BIT的光生电子-空穴的复合.
The optical and visible light catalytic properties of lanthanum-doped bismuth titanate (Bi3.25La0.75Ti3O12, BLT) nanowires prepared by one-step hydrothermal method were studied. Their crystal structures and microstructures were characterized by X-ray diffraction (XRD), transmission electron (TEM) and high resolution transmission electron microscopy (HRTEM). The results show that the prepared nanowires are pure Bi3.25La0.75Ti3O12, with an average diameter of about 25 nm. Room temperature photoluminescence (PL) The results show that the BLT nanowires have strong emission peaks near 433 and 565 nm, corresponding to exciton emission and surface defect luminescence, respectively. UV-Vis DRS shows that the bandgap energy of BLT sample is about 2.07 eV. The photocatalytic activity of BLT was evaluated by degradation of methyl orange (MO) under visible light irradiation (λ> 420nm) .The results showed that the photocatalytic activity of BLT was higher than that of commercial TiO2 catalyst P25, nitrogen doped TiO2 and pure phase bismuth titanate (Bi4Ti3O12, BIT) is much higher.The reason for the higher catalytic activity of BLT photocatalysts is that the doping of La3 + ions broadens the absorption range of BIT to visible light and suppresses the photogenerated electron-hole recombination of BIT.