Abstract:

To increase the performance of TiO2 nanotube array electrodes in solar cells, we prepared self-organized TiO2 nanotube arrays on a titaniumsubstrate 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.

Key words: Anodic oxidation, TiO2 nanotube array electrode, Quenching, Ti3+ defect