Pt-DecoratedTiO 2 Materials Supported onCarbon: Increasing Activities and Stabilities toward the ORR by Tuningthe Pt Loading

Pt nanoparticles (Pt NPs) supported on carbon have been widely employed as electrocatalysts towards the oxygen reduction kinetics. The development of more efficient electrocatalysts that enable one to reduce or even not require the use of Pt is a central challenge. In addition to the control over Pt NPs physical and chemical features, metal-support interactions can be employed to enhance activities via the generation and exposure of surface-active sites. In this context, we report herein the development of electrocatalysts composed of Pt NPs supported on TiO2 microspheres, that were subsequently impregnated onto carbon. We have found that by optimizing the loading of Pt at the TiO2 surface, the electrocatalytic activity towards the ORR could be improved compared to the commercial Pt/C (E-TEK) material, even at lower Pt loadings. The enhancement in activities could be assigned to the balance between Pt loading and generation of reactive surface sites, such as adsorbed oxygenated species. Moreover, the util...