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 TiO 2 particles dominated with {105} 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 TiO 2 could suppress the recombination of photogenerated electron–hole pairs. Thus, the Sn doped TiO 2 shows a significantly enhanced photocatalytic hydrogen evolution performance, with its hydrogen generation rate being 4.5 times higher than that of pure TiO 2 . 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.