A Novel Method for Synthesis of Titania Nanotube Powders using Rapid Breakdown Anodization

Abstract

The present paper describes a new method utilizing rapid anodization to quickly synthesize highquality, high aspect ratio, robust titanium dioxide nanotube powders. TiO 2 nanotube powders, with a typical nanotube outer diameter of approximately 40 nm, wall thickness of approximately 8-15 nm, and length of about 10-35 µm, were synthesized by potentiostatic rapid breakdown anodization of titanium foils in aqueous electrolytes of 0.3 M NaCl or 0.1 M HClO 4 under an applied potential of 20 V. High reactivity and ultrahigh reaction rate are cornerstones responsible for periodic release of TiO 2 nanotubes into solution and formation of a white precipitate of TiO 2 nanotubes. The reaction yield is approximately 4-6 g in less than 3 h, and the approximate cost of the material is $3.50/g, based on the laboratory-scale production. Various characterization techniques, including FESEM, HRTEM, EDX, XRD, XPS, FT-IR, UV-visible diffuse-reflectance, and N 2 adsorption, have been used to probe morphology, microstructure, crystallographic, composition, bond configuration, optical properties, and surface area of the nanotubes. XPS and EDX investigations show that nanotubes formed in NaCl/phosphate electrolyte solutions contain a significant amount of phosphorus species, which strongly affects crystallization and phase transformation of TiO 2 . Namely, phosphate-incorporating nanotubes stabilized the anatase phase, and initiation of the rutile phase was observed at annealing temperatures g700 °C. The resulting nanotube powders have a significant level of OH groups with a band gap ranging from 3.04 to 3.23 eV. Our results indicate that rapid breakdown anodization is highly efficient in the production of good-quality TiO 2 nanotube powders, which makes it an alternative to well-documented conventional methods.

A Study of Low-Temperature CO Oxidation over Mesoporous CuO-TiO2 Nanotube Catalysts

“…Titanium dioxide nanotubes with different microstructures and surface morphologies can be synthesized by various techniques such as rapid anodic oxidation [17], template-assisted growth [18], and the hydrothermal method [19]. Of particular interest, the hydrothermal treatment method has received great attention owing to the fairly simple synthesis, low cost processing, chemical versatility, and scalability [19][20][21][22][23].…”

A Review on TiO2 Nanotubes: Influence of Anodization Parameters, Formation Mechanism, Properties, Corrosion Behavior, and Biomedical Applications

“…Above this temperature, the anatase phase gradually transforms into rutile phase. At 700°C, the amorphous Ti becomes suppressed and transforms to crystalline Ti [189,190]. Moreover, annealing at 700°C favors sintering and tends to destroy nanostructures completely.…”

“…from the substrate and inward migration of O 2-/OH -to form crystalline oxide in a ratio that favors crystal growth, (2) the internal stress relaxation of the oxide and the tube wall became thinner by dissolution after long-time anodization, and (3) faster ion mobility in the more water containing electrolyte can offer adequate ions that favor crystal growth [190]. Higher voltages can promote the crystal phase transformation spontaneously without the application of heat treatment [195].…”

Zinc-porphyrin-imide type sensitized TiO2 nanotube arrays as photoactive electrode in a dyes sensitized solar cell

“…TiO2 is a wide band gap semiconductor, which has great ability to produce oxidants (holes in the valence band) and reductants (electrons in the conduction band) upon photons absorption [1][2][3]. Because of this feature and its mechanical strength, TiO2 has been widely studied for applications in photoelectrochemical systems, such as TiO2 photoanodes for dye-sensitized photovoltaic solar cells.…”