| TiO2 nanotube arrays fabricated through anodization have attracted significant interest and have been widely investigated due to their great potential for many applications related to the solar energy utilization for, e.g. photoelectrochemical water splitting, degradation of pollutants and solar cells etc. However, despite many efforts, it remains a major challenge to successfully in-situ fabricate crystalline TiO2. TiO2 nanotubes made by room temperature (R. T.) are generally in the amorphous state, which need to be crystallized at elevated temperatures for the photocatalytic activity. However, during crystallization treatment at elevated temperatures, a barrier layer forms between the nanotubular array and the substrate. The barrier layer reduces the electron transfer in photocatalytic processes such as water photoelectrolysis, which in turn reduces the overall water splitting efficiency. The oxide growth from the underlying Ti foil layer may percolate up and make the nanotubes dysfunctional.;The primary objective of this thesis is to explore in-situ fabrication of crystalline TiO2 nanotube arrays via anodization. Anodization at different bath temperatures and anodization potentials was investigated and a direct one-step approach for in-situ fabrication of crystalline TiO 2 nanotube arrays has been demonstrated. Research was also conducted to investigate relevant issues and elucidate mechanisms involved. |
