The Extent on the Nanoscale of Pt-Skin Effects on Oxygen Reduction and Its Influence on Fuel Cell Power

Abstract

Carbon-supported PtFe nanoparticles having similar overall composition (3:1), crystallinity, and average particle diameter were prepared with and without a Pt-skin layer and used to evaluate the extent, on the nanometer scale, of Pt-skin effects on the activity for oxygen reduction. In this study, we show that when most of the relevant properties of the catalysts are kept alike, there is an increase of about 2-fold in the intrinsic activity for oxygen reduction that can be ascribed to Pt-skin effects. It is also demonstrated that the activity improvement produced by the presence of a Pt-skin surface is, however, insufficient to generate significant differences on the power density of a single proton exchange membrane fuel cell.