A comparison of rotating disc electrode, floating electrode technique and membrane electrode assembly measurements for catalyst testing

The development of new catalysts for low temperature fuel cells requires accurate characterization techniques to evaluate their performance. As initially only small amounts of catalyst are available, preliminary screening must rely on suitable test methods. In this work, using a carbon supported platinum benchmark catalyst, the rotating disc electrode (RDE) technique was revisited in order to develop a detailed testing protocol leading to comparable results between different laboratories. The RDE results were validated by comparison with data measured both in proton exchange membrane single cells and via the relatively new floating electrode technique. This method can be operated with small amounts of catalyst but does not suffer from low limiting currents and allows prediction of high current capability of newly developed catalysts. Different durability testing protocols were tested with all three methods. Such protocols need to be able to introduce changes in the reference catalyst, but must not be too harsh as otherwise they cannot be applied to alloy catalysts. In all protocols an upper potential limit of 0.925 V was used, as this produced degradation in the chosen benchmark catalyst, but still represents realistic conditions for alloy catalysts.