Growth of TiO2 nanotubes by anodization of Ti substrates in fluoride containing media is a process that has been increasingly gaining importance as a result of its flexibility and simplicity of formation, highly ordered structure, directional pathway for electron transport and the paramount performance showed by these films in different applications such as: photocatalysis,1 photoelectrochemical solar cells,2 water splitting,3 among othersParticularly, the water oxidation has drawn attention of different researchers since it is the half-reaction occurring at the anode (TiO2 film) during photoelectrochemical water splitting.3,6-9
TiO2 nanotubes can be obtained by anodization in aqueous electrolytes as well as in organic media containing fluoride ions.1-9 The latter one is the most commonly used to fabricate films for photoelectrochemical applications due to its simplicity for controlling the morphology (tube diameter and length) through operational variables. To design these structures and provide more efficient anodes, it is necessary to understand different parameters that govern the photoelectrochemical performance of TiO2 nanotube films.
The purpose of this study is to evaluate the relation between the processing variables during the anodizing process (formation voltage and time length), over the morphology, electronic properties and photoelectrochemical performance for water oxidation, of TiO2 nanotubes film growth in 0.2 M NH4F Ethylene glycol/10% H2O.