In this project, we performed a systematic study for the spectral dependency of the photocatalytic constant of TiO2 which was fabricated by different methods and analyzed the electronic states of the used TiO2 using different approaches. We found that two simultaneous effects occur in water: an electrochemical degradation and a photocatalytic degradation of the pollutants. Furthermore, the existence of a synergetic effect was observed which is explained by the electron-hole pair separation in the electric field which increases the lifetime, even when the electric field is small.<eng>
