Anodic growth of Nitrogen-doped Titanium dioxide nanotubes by anodization process of elemental Titanium in ethylene glycol based electrolyte solution with different water contents

Anatase Nitrogen-doped Titanium Dioxide (Nitrogen-doped TiO2) nanotubes were grown via an anodization process in an ethylene-glycol based electrolyte solution containing ammonium fluoride (NH4F) and different water contents (2-4 vol%). These electrolyte solutions act as the dopants sources of Nitrogen in anodic TiO2 nanotubes. The influence of different water content of electrolyte solution on physical properties of the Nitrogen-doped TiO2 nanotubes was studied. It was observed that the diameter of the Nitrogen-doped TiO2 nanotubes was increased by the water content increasing of the electrolyte solution. Also, the Nitrogen-doped TiO2 nanotubes which grown in the electrolyte solution with 3 vol% water content had maximum length. An energy dispersive X-Ray analysis (EDX) revealed that the TiO2 nanotubes were heavily doped with Nitrogen. UV-Vis diffuse reflectance spectroscopy (DRS) and Photoluminescence (PL) measurements showed that the Nitrogen-doped TiO2 nanotubes had narrow band gap energy (lower than 3 eV).