Fabrication of MEA based on sulfonic acid functionalized carbon supported platinum nanoparticles for oxygen reduction reaction in PEMFCs

To improve the utilization and activity of cathodic catalysts for oxygen reduction reaction (ORR), platinum nanoparticles were loaded on the mixture of Vulcan XC72 and MWCNTs, which were functionalized in the mixture of 96% sulfuric acid and 4-aminobenzenesulfonic acid using sodium nitrite to produce intermediate diazonium salts from substituted anilines. The ORR performance of the fabricated membrane electrode assembly (MEA) was studied using polarization curves and electrochemical impedance spectroscopy (EIS) in a proton exchange membrane fuel cell (PEMFC). It is suggested that the improvement of the performance of the PEFC is facilitated not only by enlarging the three-phase boundary in the catalyst layer, but also by providing ionic-conduction paths as well as by imparting negative charge to platinum sites with concomitant oxidation of sulfur present in the carbon support