Oxygen reduction reaction on electrochemically deposited silver nanoparticles from non-aqueous solution

Silver was electrodeposited onto glassy carbon electrode from 0.1 mM AgClO4 acetonitrile solution containing 0.1 M LiClO4. The electrochemical deposition was carried out at constant potential of -0.5 V vs. SCE. The surface morphology was studied by scanning electron microscopy and the average particle size was determined to be 45 nm to 90 nm when increasing the deposition time from 10 s to 300 s. The rotating disk electrode (RDE) method was employed for oxygen reduction studies in 0.1 M KOH solution. It was determined that the final product for the reaction is water and the rate-determining step is the slow transfer of the first electron to O-2 molecule. The specific activities (SA) and mass activities (MA) were calculated from the RDE results and the latter was independent of the deposition time. The method used to determine electroactive surface area of Ag influenced substantially the determination of SA values.