Band structure calculation, UV-visible diffuse reflectance and photoluminescence spectroscopies were employed to investigate photophysical properties of SrSnO3. The broad luminescence band centered at 425 nm with large Stokes shift was attributed to the recombination of self-trapped excitons. Photocatalytic H-2 and O-2 evolution from water containing sacrificial reagents indicated that SrSnO3 is highly active. In particular, RuO2-loaded SrSnO3 can efficiently split pure water into H-2 and O-2 in a stoichiometric ratio under UV light irradiation. The distorted SnO6 octahedral connection seems to be favorable for effective migration of electrons or holes. The strong electron-lattice interaction in SrSnO3 might also be responsible for high photocatalytic activities. (c) 2005 Elsevier B.V. All rights reserved.