X-ray induced photoelectrochemistry on TiO2

The electrochemical behaviour of TiO2 under X-ray irradiation was studied. Under X-ray irradiation a current, a negative shift in the rest potential, and electrochemical oxidation and decomposition of [FeII(CN)6]4− were clearly observed. The incident photon-current conversion efficiency and energy conversion efficiency was 400–2000% and 0.2–2%, respectively, depending on sample conditions. These results show that the photoelectrochemical reactions were promoted by X-rays with a high incident photon-current conversion efficiency. The photocurrent and photopotential were observed above 4.965 keV, which corresponds to the Ti–K edge, indicating that electron-hole pairs are formed during the relaxation process of the excited Ti atoms.