Pt-Decorated TiO2 Materials Supported on Carbon : Increasing Activities and Stabilities toward the ORR by Tuning the Pt Loading

Abstract

Pt nanoparticles (Pt NPs) supported on carbon have been widely employed as electrocatalysts toward oxygen reduction reaction. 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 the physical and chemical features of Pt NPs, 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 toward the ORR could be improved compared to that of 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 utilization of TiO2 as support enabled improved stabilities relative to Pt/C (E-TEK). We believe that the results described herein may inspire the development of electrocatalysts for the ORR with improved activities and stabilities.