Tuning Electrocatalytic Activity of Gold Silver Nanoparticles on Reduced Graphene Oxide for Oxygen Reduction Reaction

Abstract

Gold-silver (AuAg) nanoparticles were deposited on reduced graphene oxide (rGO), with Au wt% varying from 34.6 to 46.2 and Ag wt% ranging from 31.7 to 35.3. Three AuAg/rGO samples were characterized by inductively coupled plasma optical emission spectroscopy, transmission and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray diffraction analysis. Subsequently, AuAg/rGO materials were studied using the rotating disk electrode as electrocatalysts for oxygen reduction reaction (ORR) for potential application in alkaline fuel cells. AuAg/rGO-3 (with ca. 34.6 wt% Au and 35.3 wt% Ag) showed the most promising performance, with high ORR activity and good stability, as evidenced by the highest current density (−4.45 mA cm−2 at 0.5 V), the lowest Tafel slope (103 mV dec−1), and the highest number of electrons exchanged (4.1).