Over the past 30 years, most of the works for TiO2 nanostructures have been investigated on conventionally sintered nanoparticles that are typically prepared by chemical synthesis. It is necessary to study anodic TiO2 layers in the applications for photoactive electrodes. In this work, the use of TiO2 nanotubes and mesosponges mainly in dye-sensitized solar cells (DSCs) are investigated to understand their physical, chemical and electrochemical behaviors. Additionally, for other related applications based on photoelectrochemistry, three different approaches were addressed with nanotube layers...