Surprisingly strong effect of stabilizer on the properties of Au nanoparticles and Pt^Au nanostructures in electrocatalysis.

We show that the electrocatalytic properties of nearly monodispersed Au nanoparticles (NPs) and their derived Pt-on-Au (Pt^Au) nanostructures with similarly dispersed Pt entities are dependent on the nature of stabilizers involved in the colloidal syntheses of the Au particles. The effect of stabilizer on the activity for oxygen reduction reaction (ORR) of Au NPs significantly outweighed the Au nano-size effect and thus would raise an alert to those reported size-dependent properties of metal NPs carrying various stabilizers in earlier studies. It is also demonstrated that the stabilizer effect on the property of Au NPs can further induce changes in the catalytic properties of their carried Pt. These findings clearly suggest that a proper screening of the stabilizer in the colloidal synthesis of metal NPs would be important for innovative nanomaterials and catalysts.