A carbon-aerogel-supported Pt catalyst with pore size distribution and low Pt loading has been tested in a proton exchange membrane fuel cell (PEMFC). The performance of the PEMFC and kinetic parameters of the catalyst at room temperature are discussed in terms of microstructure of the support and sulfonated tetrafluoroethylene (Nafion) distribution. The PEMFCs demonstrated power densities up to at in air∕hydrogen and backpressure on both cathode and anode. Continuous cycling with upper potential sweep limits of 1.0 and leads to degradation effects that result in decreasing of the electrochemical surface area (ESA) of the catalyst. The comparison of an ESA decrease for a 1.0 and sweep limit after indicated that the higher degradation effects are due to the oxidation of carbon support.