Rapid anodic oxidation of highly ordered TiO2 nanotube arrays

Highly ordered TiO2 nanotube arrays prepared by anodic oxidation have attracted increasing research interests due to their promising applications in many scientific areas. To the best of our knowledge, a factor limiting the application of TiO2 nanotube arrays was their long sustaining reaction time by anodic oxidation, usually lasting 6–12 h and even longer when synthesizing thicker nanotubular layers. In the present paper, we reported for the first time a facile but effective approach to accelerate the anodic formation of TiO2 nanotube arrays by proper addition of sodium carbonate (Na2CO3) into the anodization electrolyte. We adopted the 0.3 M NH4F + 0.03 M Na2CO3 + EG (ethylene glycol) + 3.0 vol.% H2O electrolyte and the average growth rate of the nanotubes achieved in our experiments could be accelerated to 1100 nm/min. The possible mechanism of the rapid electrochemical process was also presented.