Analytical Procedure for Accurate Comparison of Rotating Disk Electrode Results for the Oxygen Reduction Activity of Pt/C

Rotating disk electrode (RDE) voltammetry has been touted as a simple means for benchmarking the oxygen reduction reaction (ORR) activity of platinum-based electrocatalysts in proton exchange membrane fuel cells. In practice, the RDE methodology has been highly variable across laboratories, with up to 20% differences in values for the Pt electrochemical surface area and 10x differences in mass activity and area-specific activity reported from the same standard Pt/C electrocatalyst. We confirm that the same ORR activities can be replicated across laboratories when a detailed experimental protocol is followed. From our work and others', we conclude that dominant factors in the RDE experimental protocol include the ink formulation, electrocatalyst film quality and the electrochemical procedures. We make a recommendation for procedures for the reproducible characterization of Pt/C commercial catalysts, present simple metrics for researchers to use for a quick check of their results, and also propose new benchmark values for two Pt/C standards. (C) 2014 The Electrochemical Society.