Enhancing photocatalytic activity of Sn doped TiO2 dominated with {105} facets

Electronic structures of semiconductor photocatalysts control the light absorbance, charge-carrier separation and mobility, activation energy and consequently, photocatalytic activity. Ion doping has been widely used to modify the electronic structure of a semiconductor photocatalyst. Here, we successfully synthesized Sn doped single crystalline anatase TiO2 particles dominated with {1 0 5} facets by a gas phase oxidation process, and their structure and composition were thoroughly analyzed by XRD/TEM/FESEM/XPS. The photoluminescence emission spectra measurements reveal that the small amount of doped Sn in TiO2 could suppress the recombination of photogenerated electron-hole pairs. Thus, the Sn doped TiO2 shows a significantly enhanced photocatalytic hydrogen evolution performance, with its hydrogen generation rate being 4.5 times higher than that of pure TiO2. First-principle simulation results suggest the doped Sn at the edge exhibit higher adsorption energy toward H, which could promote the H-2 generation from the splitting of water. (C) 2013 Elsevier B.V. All rights reserved.