TiO2 nanotube arrays are considered as ideal photo-anodes
in photoelectrocatalytic applications, due to their stronger lightharvesting
scattering effects and slower charge recombination than
randomly packed zero-dimensional nanoparticle films [10–14].
Nevertheless, there are still some issues to be resolved, which limit
their performance. One of these issues is to balance the efficiency of
charge separation and surface area. The latter one can be the determining
factor in promoting photodegradation by enhancing active
sites and the adsorption for reactant molecules [15–17]. To increase
the length of nanotube is an effective way to improve the surface