Enhanced photocatalytic hydrogen evolution over nanometer sized Sn and Eu doped titanium oxide

A series of Sn and Eu doped TiO2 (Ti1-(x+0.001)Eu0.001SnxO2-delta where 0.05 < x <0.3) nanoparticles have been synthesized by polyol method. Pure TiO2 and TiO0.949Eu0.001Sn0.05O2-delta existed as anatase phases whereas the compositions with higher Sn concentrations contained mixed anatase and rutile phases. The particle size of these nanocrystalline samples was similar to 10 to 15 nm. All compositions showed an onset of absorption at similar to 450 nm. Photocatalytic activity for hydrogen generation from water-methanol mixture was tested for these samples using sunlight type radiation. Among these catalysts, Ti0.949Eu0.001Sn0.005O2-delta exhibited significantly high activity for hydrogen generation with a quantum efficiency of similar to 40% with Pd as co-catalyst. The enhanced activity is attributed to the visible light absorption arising, due to the defects associated with the oxygen vacancies and due to the increased reductive power of the composite system. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.