Hierarchical Wall Formation of Titanium Oxide Nanotube Arrays Using Anodic Oxidation

Hydrolytic reaction of TiF 6
^2-
induces in situ titanium dioxide (TiO
₂
) nanorings deposition during a TiO
₂
nanotube array (TONA) preparation by electrochemical anodization. This deposition leads to a reduction of the electric field and the current density beneath the TiO
₂
nanorings, thus inducing tube wall separation, and results in the formation of a tubular TONA structure. The TiF 6
^2-
hydrolytic reaction can also be used to modify the morphology of TONA, which leads to a convenient route to fabricate the novel structures of TONAs for possible new applications.