Synthesis of Pd and Nb-doped TiO2 composite supports and their corresponding Pt-Pd alloy catalysts by a two-step procedure for the oxygen reduction reaction

► Highly conductive Pd-Nb0.06Ti0.94O2 supports were obtained with the addition of Pd. ► The supported Pt-Pd catalysts were prepared by a polyol deposition method. ► The conductivity of support increased with increasing content of Pd. ► Pt-Pd nanoparticles adhered to Pd-Nb0.06Ti0.94O2 surfaces to form PtmPdn clusters. ► PtmPdn facilitate the dissociation of O2 on the Pt surface and enhance ORR activity.