Performance of PEFC Formed by Using Pt-Loaded Activated Carbon under High- and Low-Humidity Conditions

The enhancement of oxygen reduction at the catalyst layer formed from a Pt-loaded conventional activated carbon with adsorbed compared to that from Pt/carbon black was recently found using rotating disk electrodes (RDEs). In this study, we verified the enhancement at fuel cells formed by using carbon in the cathode catalyst layer. The layer was formed with various Nafion loadings to investigate its influence on the performance. The influence of humidity of the reactant gases was also investigated. It was found that the cathode formed from the required a higher Nafion content than the cathode to produce the optimized performance. At a relative humidity of 100%, the polymer electrolyte fuel cell (PEFC) formed from showed better performance than that formed from the in the cathodes. The adsorption of onto further improved the performance. This tendency was in agreement with the results of the RDE measurements. At a relative humidity of 25%, although the hydrophilicity of the catalysts affected the kinetics of oxygen reduction and the cell resistance, the same tendency of the PEFC performance was observed. The results suggest the usefulness of with for improvement of PEFC performance.