Nanotubos de orientación vertical autoensamblados por método electroquímico: síntesis y caracterización

Abstract

Nanotube arrays of TiO2 have received great attention in various areas, such as gas- sensing, photocatalysis, solar energy conversion, and biomaterials. Therefore, particular attempts are carried out to fabricate the vertically oriented TiO2 nanotube arrays by electrochemical anodization in order to improve its properties to meet the practical application requirements. In the present work, vertically oriented TiO2 nanotube arrays have been fabricated by a selforganized electrochemical anodization process of titanium foil by use of glycerol based electrolyte (containing 0.27M NH4F and 50 vol% H2O). The effect of anodizing potential and growing time in the final TiO2 resulting nanostructure has been studied and discussed. XRD and SEM analysis were employed to characterize crystallographic phase, the overall crystalline quality, the possible texture of the nanotubes, and the morphological nanotube properties. In the present work the wetting properties of the nanoporous TiO2 nanotube structure have also been studied to determine the hidrophobic and hidrophylic grade. Ordered high-aspect-ratio TiO2 nanotube arrays with an inner-tube diameter of ca. 35 nm and a tube height of several tens of microns have been obtained. As confirmed by X-ray diffraction studies, the as-prepared TiO2 nanotubes are amorphous but crystallize with annealing in an oxygen atmosphere at 550 oC, exhibiting then, the anatase phase with a minor quantity of the rutile one.