Influence of the Re introduction method onto Pd/TiO 2 catalysts for the selective hydrogenation of succinic acid in aqueous-phase

•Bimetallic catalysts were prepared by two protocols, i.e. successive impregnation (SI) or surface redox reduction (CR).•The localization of the Re deposit on the Pd catalyst surface varied according to the Re introduction mode.•The CR method induced a selective Re deposit at the Pd–TiO2 interface compared to a random distribution obtained by SI.•The oxidation state of the Re species (Re3+, Re0) on the reduced bimetallic samples was linked to their preparation mode.•The modification of Pd/TiO2 catalysts by Re allowed hydrogenating selectively succinic acid to 1,4-butanediol in aqueous solution.