Enhancement of visible light-induced hydrophilicity on nitrogen and sulfur-codoped TiO2 thin films

We fabricated N, S-codoped, N-doped, S-doped TiO2 anatase thin films by a radio-frequency (RF) sputtering method and evaluated the photoelectrochemical and photoinduced hydrophilic activities. The N, S-codoped TiO2 thin film showed obviously higher activities than either the N-doped or S-doped TiO2 under visible light irradiation. The photoinduced hydrophilic activity of the N, S-codoped TiO2 was also greater than that of the undoped TiO2 even under fluorescent light bulb, which contained both visible and UV lights. The high activities of the N, S-codoped TiO2 could be attributed to the hybridization of the introduced N 2p and S 3p, which was supported by the results of ab initio calculations. (C) 2008 Elsevier Ltd. All rights reserved.