While titania nanotubes are expected to have important applications in the photoelectrochemical production of hydrogen, it is found that surface-adsorbed ions on the nanotube surface, specifically alkali ions, have a significant impact on the photoelectrochemical water-splitting characteristics. Such surface-adsorbed alkali ions are invariably a result of the electrochemical fabrication process which uses an alkali-based electrolyte for the production of vertically aligned array of titania nanotubes. The presence of surface-adsorbed ions is revealed in synchrotron-based near edge X-ray absorption fine structure (NEXAFS) studies. Photoelectrochemical behavior of such surface-adsorbed titania nanotubes is found to be significantly altered when compared with pure titania nanotubes which may be explained in terms of a simple phenomenological model predicting modifications to the energy band structure of titania as a result of surface adsorption.