Facile synthesis of supported Pt–Cu nanoparticles with surface enriched Pt as highly active cathode catalyst for proton exchange membrane fuel cells

Carbon supported Pt–Cu catalyst (PtCu/C) with surface enriched Pt was synthesized by annealing the Pt-deposited Cu particles. X-ray diffraction (XRD) results indicate the formation of disordered Pt–Cu alloy phase with a high level of Cu/Pt atomic ratio. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) analysis confirm the surface enrichment of Pt. Electrochemical measurements show that PtCu/C has 3.7 times higher Pt mass activity toward the oxygen reduction reaction (ORR) than commercial Pt/C. The enhanced ORR activity of PtCu/C is attributed to the modified electronic properties of surface Pt atoms, which reduces the surface blocking of the ORR oxygenated species.