Oxygen reduction reaction on electrodeposited PtAu alloy catalysts in the presence of phosphoric acid

• Phosphate adsorption on Au substrate was investigated by in situ EC-SERS.
• Under acidic condition, Au has strong tolerance to phosphate species adsorption.
• ORR activities of electrodeposited PtAu alloys were tested in the presence of PA.
• PtAu catalysts exhibited better ORR activity than pure Pt in the presence of PA.

We have investigated phosphate adsorption on the Au surface by in situ electrochemical surface-enhanced Raman spectroscopy to assess the possible use of Au-based alloys as catalysts for the oxygen reduction reaction (ORR) in high-temperature proton exchange membrane fuel cells. Compared with its strong adsorption in neutral or basic electrolytes, the adsorption of phosphate species on the Au surface were significantly altered in acidic electrolyte. Thus, PtxAu100-x catalysts of various compositions were prepared by electrodeposition and exhibited better ORR activities than pure Pt in phosphoric acid electrolyte, which can be explained in terms of alloying effects and the different phosphate adsorption behavior.

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