Site-specific deposition of metal nanoparticles (NPs) on metal oxide surfaces is challenging but of particular importance for the development of catalytic materials with improved or new performance. We report here that Ru NPs can be directed to the rutile/anatase junction of P25 TiO2 via a facile wetness impregnation-chemical reduction method at room temperature. In the partial hydrogenation of benzene to cyclohexene, the Ru/P25 catalyst outperformed the Ru NPs supported on phase-pure rutile and anatase as well as physically mixed Ru/rutile and Ru/anatase, both in activity and in selectivity. We identified a unique electron-deficient Ru species (Ru delta+) on the Ru/P25 catalyst originated from the Ru-O linkages connecting the Ru NPs with the rutile/anatase junction. This interfacial Ru delta+ species gave rise to an especially tightly bonding benzene species while lowering the adsorption strength of cyclohexene, thus granting the Ru/P25 catalyst superior activity and unprecedented selectivity toward cyclohexene (initial selectivity 90%). (C) 2015 Elsevier Inc. All rights reserved.