Proton Conductivity within Fuel Cell Electrodes Containing a Sulfonated Carbon Support

Abstract

Sulfonic acid functionalities were grafted onto the surface of Pt/Vulcan XC72 electrocatalysts via the thermal decomposition of ammonium sulfate method. Electrochemical impedance spectroscopy was used to investigate its impact on catalyst utilization and proton conductivity as a function of depth within the catalyst layer. Catalysts prepared from sulfonated carbon supports displayed higher electrochemically active surface areas at lower Nafion contents than those prepared from untreated carbons. This enhanced conductivity and active area was explained in terms of an increased concentration and more effective deployment of sulfonic acid groups.