The interaction of water with wide band gap metal oxides has wide ranging applications. Using first principles approach we demonstrate that a mixed oxide of SnxT1-xO2 (x = 0.5) significantly reduces the dissociation barrier of water in comparison to SnO2 and TiO2 surfaces. From the charge distribution at the top layer it is seen that SnxT1-xO2 is more polar, where the charge separation between metal and oxygen atoms is more than SnO2 and TiO2 surfaces. The reason behind higher activity of the mixed surface has been explained by the surface morphology and larger surface charge density at the top layer. (C) 2015 Elsevier B.V. All rights reserved.