Durability of carbon–silica supported catalysts for proton exchange membrane fuel cells

Carbon-aerogel silica composite material is evaluated as an alternative catalyst support material for Proton Exchange Membrane (PEM) fuel cells. Brunauer–Emmett–Teller surface areas of these materials are usually higher than Vulcan XC-72 which enabled a homogeneous catalyst distribution. Performance of the Membrane Electrode Assemblies (MEAs) prepared with C-SiO2 supported platinum catalysts increased with low silica content and decreased at higher levels. Performances up to 0.31 W cm−2 at 0.8 V are obtained with silica containing MEAs whereas only 0.23 W cm−2 at 0.8 V could be obtained with silica free MEAs. On the other hand, durability of the MEAs increased with increasing silica content. Accelerated durability tests show a current drop of 22–40% (at 0.6 V) for silica containing MEAs compared to 40% (at 0.6 V) for silica-free MEAs. Although appearing to have improved durability, silica containing MEAs show hydrophilic behavior, especially at high current density.

► Membrane Electrode Assemblies (MEAs) were prepared and tested from C-Aerogel SiO2 composite catalyst support materials with different SiO2 concentrations. ► Increased surface area was observed with C-SiO2 composites. ► Improved fuel cell performance results were obtained with SiO2 modified catalysts. ► Improved durability was observed with SiO2 modified catalyst containing MEAs.