Cyclic Voltammetry for Synthesizing Carbon Supported Pt-Cu Alloy with Superior Oxygen Reduction Activity

Cyclic voltammetry (CV) was used to fabricate carbon supported Pt-Cu alloy (Pt-Cu/C) for oxygen reduction reaction (ORR) at ambient temperature. A flowerlike structure of Pt-Cu nanoparticles were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy was used to confirm the surface chemical composition and metallic state. And, electrochemical measurements such as CV, rotating disk electrode, rotating ring-disk and electrochemical impedance spectroscopy were applied to obtain the kinetic constants and the reaction mechanisms of the ORR. Compared with Pt/C, Cu/C, Pt-Cu/C exhibits the highest efficient catalytic activity for ORR, as evidenced by the highest current densities of the polarization curves, lowest onset oxidation potential and charge transfer impedance. The average electron transfer number and hydrogen peroxide calculated from RRDE are about 3.87 and 6.71%, respectively. These results show that the synthesized Pt-Cu/C has excellent electrocatalytic activity and the ORR is a four-electron dominant reduction pathway.