Non-chapped, vertically well aligned titanium dioxide nanotubes fabricated by electrochemical etching

Abstract

This paper reports on the fabrication of non-chapped, vertically well aligned titanium dioxide nanotubes (TONTs) by using electrochemical etching method and further heat treatment. Very highly ordered metallic titanium nanotubes (TNTs) were formed by directly anodizing titanium foil at room temperature in an electrolyte composed of ammonium fluoride (NH 4 F), ethylene glycol (EG), and water. The morphology of as-formed TNTs is greatly dependent on the applied voltage, NH 4 F content and etching time. Particularly, we have found two interesting points related to the formation of TNTs: (i) the smooth surface without chaps of the largely etched area was dependent on the crystalline orientation of the titanium foil; and (ii) by increasing the anodizing potential from 15 V to 20 V, the internal diameter of TNT was increased from about 50 nm to 60 nm and the tube density decreased from 403 tubes μm −2 down to 339 tubes μm −2 , respectively. For the anodizing duration from 1 h to 5 h, the internal diameter of each TNT was increased from ∼30 nm to 60 nm and the tube density decreased from 496 tubes μm −2 down to 403 tubes μm −2 . After annealing at 400 °C in open air for 1 h, the TNTs were transformed into TONTs in anatase structure; further annealing at 600 °C showed the structural transformation from anatase to rutile as determined by Raman scattering spectroscopy.

Hierarchical mesoscale assembly of PbO2on 3D titanium felt/TiO2nanotubular array electrode for anodic decolourisation of RB-5 dye

“…Raman spectroscopy revealed the structural properties of coatings related to the presence of PbO 2 and formation of anatase phase after annealing as shown in figure 5(a). The distinct Raman peaks were observed at 428 cm −1 and 137 cm −1 which showed the presence of PbO 2 [35] and the effect of annealing in transforming the substrate to anatase phase, as indicated by previous research [36]. In figure 5(a), no significant anatase peaks were observed before calcination, showing that the hydrothermal synthesis of PbO 2 at 60°C did not significantly affect the structure of the titanium phase.…”

Visible-Light Active Titanium Dioxide Nanomaterials with Bactericidal Properties

“…The growth of TNT arrays is described as the competition between electrochemical oxide formation and chemical dissolution of oxide by F − ions of sufficient concentrations [222][223][224]. Figure 13a,b shows the formation of TNT arrays by anodizing Ti in a mixed ethylene glycol/NH 4 F and water solution [223,225]. At a low applied voltage of 5 V, an SEM image shows the formation of the rough Ti surface together with inhomogeneous TNTs.…”

Capturing Irradiation with Nanoantennae: Plasmon‐Induced Enhancement of Photoelectrolysis

“…This makes the SERS intensity highly dependent on the cavity diameter and height and the resulting plasmonic modes 55,62,85 . The annealing temperature also influences the intensity of Raman bands, typically increasing with temperature as the crystallinity improves [122][123][124][125] . All the aforementioned aspects are summarized in the bar chart below (cf.…”