Study of the highly ordered TiO 2 nanotubes physical properties prepared with two-step anodization

摘要

Highly ordered hexagonal closely packed titanium dioxide nanotubes (TiO2NTs) were successfully grown by a two-step anodization process. The TiO2NTs were synthesized by electrochemical anodization of titanium foils in an ethylene glycol based electrolyte solution containing 0.3?wt% NH4F and 2?vol% deionized (DI) water at constant potential (50?V) for 1?h at room temperature. Physical properties of the TiO2NTs, which were prepared via one and two-step anodization, were investigated. Atomic Force Microscopy (AFM) analysis revealed that anodization and subsequently peeled off the TiO2NTs caused to the periodic pattern on the Ti surface. In order To study the nanotubes morphology, Field Emission Scanning Electron Microscopy (FESEM) was used, which was revealed that the two-step anodization resulted highly ordered hexagonal TiO2NTs. Crystal structures of the TiO2NTs were mainly anatase, determined by X-ray diffraction analysis. Optical studies were performed by Diffuse Reflection Spectra (DRS) and Photoluminescence (PL) analysis showed that the band gap of TiO2NTs prepared via two-step anodization was lower than the band gap of samples prepared by one-step anodization process.