银掺杂TiO2纳米管制备与性能研究

常压碱熔-水热法制备了银掺杂TiO2复合纳米管。氮吸附法测定其比表面积与原料相比,增加了2.3倍,达82m2/g。用XRD、TEM和XPS进行了表征。TiO2纳米管由锐钛矿相和金红石相组成,研究表明复合纳米管中银元素以金属银和氧化银状态共存。因长径比增大,其XRD衍射峰峰高和峰强均大幅度降低。UV-Vis吸收光谱显示,银掺杂TiO2复合纳米管的吸收光谱发生了红移,带边红移近40nm。这是因为在TiO2纳米管表面形成了肖特基结,TiO2禁带宽度之间形成了杂质能级,使其表观禁带宽度减小,有助于光生电子的迁移,减少电子-空穴复合;纳米管表面羟基氧(—OH)使其表面的酸性活性点增加,增强了价带中光生空穴的氧化能力。

Synthesis and characterization of Ag-doped TiO2 nanotubes

Composite TiO2 nanotubes with Ag-doped were synthesized for the first time using the alkaline fusion and hydrothermal method under ambient atmosphere.Compared with the raw materials increased 2.3 times,the specific surface of TiO2 nanotubes was 82m2/g by nitrogen adsorption.The nanotubes were then characterized by XRD,TEM and XPS techniques.Research demonstrates that metal silver and silver oxide coexisted in the composite TiO2 nanotubes which were composed of anatase and rutile.Since the ratio of length to diameter rose,both height and intensity of the diffraction peak decreased significantly.UV-Vis absorption spectra of TiO2 nanotubes were shifted by 40nm for Ag-doped.This is because of the formation of Schottky on the surface of TiO2 nanotubes and formation of impurity level between TiO2 band gaps.Decrease in the apparent band gap contributed to the migration of photoelectrons,reducing the electron-hole recombination.The acidic active sites were increased by the hydroxyl(—OH) on the surface of TiO2 nanotubes,which enhanced the photo-oxidation of holes in the valence band.