Fabrication of TiO2 nanotube arrays by electrochemical anodization in an NH4F/H3PO4 electrolyte

• Published in: Thin solid films 2011-07, Vol.519 (19), p.6459-6466
• Main Authors: RUI LIU, YANG, Wein-Duo, QIANG, Liang-Sheng, WU, Jian-Fu
• Format: Article
• Language: English
• Subjects: Anodizing; Arrays; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrolytes; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Field emission, ionization, evaporation, and desorption; Materials science; Methods of nanofabrication; Morphology; Nanocomposites; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotubes; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Titanium dioxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.04.231

Highly ordered TiO2 nanotube arrays were fabricated by electrochemical anodization of titanium in an NH4F/H3PO4 electrolyte. A TiO2 crystal phase was identified by X-ray diffraction, and the morphology, length and pore diameter of the TiO2 nanotube arrays were determined by field-emission scanning electron microscopy (FE-SEM). The anodization parameters including the rate of magnetic stirring, F- concentration, calcination temperature, anodization voltage and anodization time were investigated in detail. The results show that the as-prepared TiO2 nanotube arrays possessed good uniformity, a well-aligned morphology with a length of 750nm and an average pore diameter of 62nm at a 150rpm rate of magnetic stirring for 120min at 20V in an electrolyte mixture of 0.2M H3PO4 and 0.3M NH4F with a 500 degree C calcination to obtain 100% anatase phase. The adsorption of N-719 dye at different tube lengths was determined by UV-vis analysis and found to increase with increasing tube length. We also discuss the formation mechanism of the TiO2 nanotube arrays. The findings indicate that the formation of the TiO2 nanotube arrays proceeds by the combined action of the electrochemical etching and chemical dissolution.