Investigation of the Oxygen Reduction Activity on Silver - A Rotating Disc Electrode Study

In this study the oxygen reduction reaction (ORR) is investigated on a nanoparticulate silver electrocatalyst in alkaline solution. The catalytic activity of the catalyst is determined both in terms of mass activity as well as specific activity and turn over frequency, respectively. It is demonstrated that the established mass activities are independent of the applied catalyst loading, an essential requirement for a reasonable analysis. The determination of the electrochemically active surface area (ECA) or the number of electrochemically accessible sites (N-ECAS), respectively, is performed by the under-potential deposition of lead. The obtained value of the activity is compared to activities of polycrystalline silver and platinum measured in the same electrolyte, as well as to literature data.