Redox-transmetalation of Pt/Au catalyst for oxygen reduction reaction

A Pt/Au/C core-shell catalyst was developed for oxygen reduction reaction by using a surfactant-free chemical reduction and a subsequent electroless redox-transmetalation method. A full coverage of the Au core (∼30 nm) by the Pt nanoparticles (∼5 nm) was achieved after 48 h of redox-transmetalation time which was confirmed by UV-Vis, TEM and electrochemical measurements. The electrocatalytic activity of the as-prepared Pt/Au/C towards ORR was studied in 1 M H2SO4 by means of rotating disk electrode investigations. The Pt + Au mass-normalized activity of Pt/Au/C was found to be 2 times higher than that measured at Pt/C. In the high current densities region, however, a Tafel slope of 143 mV was calculated for Pt/Au/C_48 h, compared to 120 mV for Pt/C. The novel catalyst showed a higher methanol tolerance and improved stability compared to the Pt/C reference one.