ABSTRACT
Titanium dioxide (TiO2) has been widely employed in dye-sensitized solar cells (DSSCs) [1,2], biosensors [3], hydrogen sensors [4], and water photolysis [5] due to its various intriguing properties. Among diverse one-dimensional nanostructures, highly oriented TiO2 nanotube arrays prepared by electrochemical anodization have been vigorously investigated since it was first reported in 1999 [6]. The highly ordered structure obtained is much more favored comparing to the randomly packed configuration presented by the sol-gel method [7], e.g., for application in DSSCs. And the nanotube geometry can be tailored by changing experimental parameters [8-13], superior to template-assisted synthesis where the geometry is limited and controlled by the original template [14].
