Preparation and Photocatalytic Performance of Self-Doped TiO2 Nanotube Arrays in Liquid Environment

A facile reduction strategy using N2H4 center dot 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 self-doped 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.