Preparation of carbon supported platinum decorated on gold nanoparticles for proton exchange membrane fuel cells.

Abstract

Platinum/Gold (Pt/Au) nanoparticles with different Pt/Au ratio ranging from 0.5 to 2.0 with Au core size of 2nm in diameter were synthesized using the reduction method. Besides, for Pt/Au of 1.0, different gap filling coverage were synthesized by adding different amount of Au after the basic Pt/Au nanoparticles were formed to fill the gaps between the Pt atoms/islands. These catalysts were then characterized using Transmission electron microscopy, X-ray diffraction and voltammetry methods. The lower Pt/Au ratio showed increasing better electrocatalytic activity using formic acid as an electrolyte. These decorated catalysts all demonstrated better activities than the usual Pt/C catalyst. Moreover, with increased in gap filling coverage for the Pt/Au of 1.0, the activity towards formic acid also increases. This can be account by the fact that the additional Au particles were “inserted” between the Pt atoms and prevented the Pt atoms from segregating together thus reducing the ensemble effect. This effect was further proven by conducting the Methanol oxidation experiment which showed that the gap filling catalysts were more resistant to methanol oxidation than the basic Pt/Au catalyst.