Effect of Quenching on Properties of TiO<sub>2</sub> Nanotube Arrays

Abstract

To increase the performance of TiO2 nanotube array electrodes in solar cells,we prepared self-organized TiO2 nanotube arrays on a titanium substrate in 0.5%(w,mass fraction) NH4F/glycerol by anodic oxidization at a constant potential. The electrodes were then quenched in water at different temperatures. These quenched TiO2 nanotube array electrodes were then characterized by X-ray diffraction(XRD) ,field emission scanning electron microscopy(FESEM) ,X-ray photoelectron spectroscopy(XPS) and cyclic voltammetry(CV) . Experimental results indicated that the quenching process produced many surface defects and also resulted in fragmentation of the TiO2 nanotubes. We found that the sample quenched in water at 0 ℃ contained the more Ti3+ surface defects,OH groups and nanotube fragments. These properties improved its photoelectrochemical performance significantly. This sample resulted in 96.2% photodegradation rate of methyl orange after irradiation for 40 min.