Semi-empirical evaluation of PEMFC electro-catalytic activity.

The investigation of the performance of small single PEMFC was carried out by employing a purposely designed test bench with complete control of the operational parameters. A MEA preparation method was also developed constituting the base for testing new electrocatalytic materials or improved electrode assembling techniques. Beyond determining the polarization curves, other tests have been carried out like electrical resistance measurement by the current interruption method and voltammetric characterization. A semi-empirical approach based on a simplified mathematical model has been used to fit the experimental polarization data, providing useful parameters for evaluating the electrocatalytic activity together with other significant data of the MEA performance. The analysis of polarization curves includes the determination of the OCV by considering the mixed potential at the oxygen electrode by fitting the initial data with an arbitrary oxidation reaction. This can provide an estimate of hydrogen crossover. Possible change of ohmic resistance with current intensity is discussed. The preliminary results, demonstrating the feasibility of the method are reported.