Influence of Electrolyte Composition on Morphology of Titanium Dioxide Films Obtained by Titanium Anodization in a Circulated Mixing Cell

Highly ordered films from individual TiO(2)nanotubes (NTs) with controlled geometric characteristics were obtained by potentiostatic anodization of titanium in an electrochemical cell with flow-through circulation of the solution and a cooling system for it placed outside the cell at a temperature of 25 +/- 0.5 degrees C. The study shows how a wide concentration range of water (0-15%) and ammonium fluoride (0.1-2.0%) in ethylene glycol (EG) influences the morphology and composition of the obtained TiO2NTs. It was found that the most ordered structure of TiO2NTs forms when the water content in the anodizing solution is 0.5-4.0% and the proportion of NTs in the hexagonal coordination reaches 75%. It is shown that fluoride ion and water concentration in EG do not affect the chemical state and concentration of elements in the resulting nanostructures. X-ray photoelectron spectroscopy revealed that titanium in the obtained samples is in the form Ti(4+)and Ti(3+)with a relative proportion of the latter of 8 +/- 2%.