自掺杂TiO_2纳米管:液相制备及光催化性能

Preparation and Photocatalytic Performance of Self-Doped TiO_2 Nanotube Arrays in Liquid Environment

采用水合肼(N2H4·H2O)作为还原剂,在液相环境中制备了自掺杂TiO2纳米管阵列(NTs)。利用FE-SEM、EDS、XPS、XRD、Raman、UV-Vis/NIR分光光度法以及半导体特性分析系统(Keithley 4200 SCS)分别对样品的形貌,晶体结构,光学特性以及电学性能进行了表征。结果表明:通过这种方法制备的自掺杂TiO2NTs在带隙中引入了大量的氧空位,创造了氧空位能级,从而提高了样品的电导率,有效提高光生电子-空穴对的产生、分离和传输。此外,由于氧空位的作用,使得TiO2NTs的带隙变窄,增强了可见光吸收能力,致使样品具有较高的光催化活性,并通过降解甲基橙溶液对样品的光催化活性进行评估。结果显示当光照150 min后,自掺杂TiO2NTs对甲基橙溶液的降解率达73%,并且这种催化剂便于回收和重复使用。

A facile reduction strategy using N2H4·H2O to yield self-doped TiO2 nanotube arrays（NTs） is proposed in a liquid environment in this work. The morphology, crystalline structure, optical and electrical properties of the as-grown specimens are characterized by using FE-SEM, EDS, XPS, XRD, Raman, UV-Vis spectroscopy and semiconductor characterization system（Keithley 4200 SCS）, respectively. The results show that a lot of oxygen vacancies are introduced into the band gap of the TiO2 NTs and the oxygen vacancy level is created, thus improving the conductivity of the samples and facilitating photogenerated electron-hole separation and carriers transport under simulated solar light irradiation. Moreover, due to the effect of oxygen vacancies, the band gap of specimens is narrowed, and visible light absorption ability enhanced. Compared with pristine TiO2 NTs, the selfdoped TiO2 NTs have higher photocatalytic activity as evaluated by degradation rate of methyl orange solution.The degradation rate is more than 73% after 150 min light irradiation. Meanwhile, this kind of catalyst is easy to recycle and reuse.