Preparations and photocatalytic hydrogen evolution of N-doped TiO2 from urea and titanium tetrachloride

Nitrogen (N)-doped TiO(2) samples with high specific surface areas were directly prepared by heating the mixture of urea and TiO(2), where the TiO(2) was obtained with titanium tetrachloride as precursor. The absorption spectrum of the N-doped TiO(2) shifted to wavelength up to 600 nm with increasing urea contents. X-ray photoelectron spectroscopic measurements showed that the N presented in TiO(2) was in the state of both molecularly chemisorbed N(2) and substituted N. While both of them contribute to the response to visible light, the latter gave the prepared samples with hydrogen evolution under visible light. The apparent photocatalytic activity of water splitting demonstrated as high amount of H(2) evolution was partly due to the phase transformation from anatase to rutile for the N-doped TiO(2). (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.