Preparation of Pt–Au/carbon catalysts by a reduction method and their electrocatalytic activities for oxygen reduction reactions

Abstract

Platinum and gold supported on carbon catalysts with various Pt/Au ratios were prepared by a reduction method for use as the cathode in a proton exchange membrane fuel cell (PEMFC). The Pt/Au ratio was controlled by varying the concentration of each component in the solution, and the influence of the composition on the electrocatalytic activities during an oxygen reduction reaction (ORR) was investigated.The crystallinity of the synthesized materials was investigated by X-ray diffraction, and the oxidation state of both the platinum and gold was determined by X-ray photoelectron spectroscopy (XPS). The particle size of the Pt–Au was analyzed by TEM (transmission electron microscopy). The electrocatalytic activity for oxygen reduction was evaluated using a rotating disk electrode system. The results show that activity and stability were found to be strongly dependent on the electrode composition (Pt/Au ratio). Synthesized electrodes were also employed as cathodes in MEA, and the performance of a PEM (polymer electrolyte membrane) fuel cell was evaluated.