Bi3.25Nd0.75Ti3O12纳米结构: 可控合成及其可见光催化活性

用水热法制备不同形貌的掺钕钛酸铋(Bi3.25Nd0.75Ti3O12,BNdT)纳米粉体.透射电子显微镜(TEM)结果表明,通过控制OH-浓度可以得到不同形貌的纳米粉体.基于不同条件下制备的样品微结构分析,提出了这些不同形貌的形成机制.紫外-可见漫反射光谱(UV-Vis DRS)表明BNdT样品的带隙能(Eg)约为1.984 eV.利用可见光照射下甲基橙降解实验评价了BNdT样品的光催化性能.结果表明,BNdT的光催化活性比商用TiO2催化剂P25和掺氮TiO2高得多.OH-浓度为10 mol·L-1时制备的BNdT纳米线光催化效率最高,经可见光照射360min,浓度为0.01 mmol·L-1甲基橙溶液的降解率可达到93.0%,且循环使用4次后,其光催化活性并没有明显降低,表明BNdT是一种稳定有效的可见光催化剂.

Bi3.25Nd0.75Ti3O12 Nanostructures: Controllable Synthesis and Visible-Light Photocatalytic Activities

Neodymium-doped bismuth titanate(Bi3.25Nd0.75Ti3O12,BNdT) nanostructures with different morphologies were synthesized hydrothermally without using surfactant or template.Transmission electron microscopy(TEM) results showed that different morphologies could be fabricated simply by manipulating the concentration of OH ions during hydrothermal synthesis.Hydroxide ions played an important role in controlling the formation of seeds and the growth rate of BNdT particles.On the basis of structural analysis of samples obtained under different conditions,a possible mechanism for the formation of these distinctive morphologies was proposed.A UV-visible diffuse reflectance spectrum(UV-Vis DRS) of an as-prepared BNdT sample revealed that its band gap energy(E g) was about 1.984 eV.BNdT photocatalysts exhibited higher photocatalytic activities for the degradation of methyl orange(MO) under visible light irradiation than those for traditional commercial P25 TiO2 and N-doped TiO2(N-TiO2).BNdT nanowires prepared using a hydroxide concentration of 10 mol·L-1 showed the highest photocatalytic activity among the samples.Over this catalyst,93.0% degradation of MO(0.01 mmol·L-1) was obtained after irradiation with visible light for 360 min.In addition,there was no significant decrease in photocatalytic activity after the catalyst was used 4 times,indicating that BNdT is a stable photocatalyst for degradation of MO under visible light irradiation.