Particle Design and Evaluation for Electrocatalysts of Polymer Electrolyte Fuel Cells

In proton exchange membrane fuel cells operating with the use of Pt catalyst supported on carbon (Pt/C) cathode catalysts, severe corrosion of the carbon support has been recognized at high potentials. Highly catalytic durability with high activity is required toward the application of heavy-duty use. One of the alternative candidate catalysts are Pt catalysts supported on non-carbon ceramic supports. Our group invented that Pt catalysts supported on SnO2 and CeO2 without carbon additive. These catalysts were superior in durability (startup/shutdown, load cycling) and oxygen reduction reaction activity to those of commercial Pt/C by evaluation of membrane-electrode assemblies. The non-carbon support of SnO2 nanoparticles has a unique carbon-like microstructure consisting of a fused-aggregate network structure, which enhances the electronically conducting pathways via the aggregated microstructure and gas diffusion pathways via the open pores in the microstructure. The cell performance using the Pt/SnO2 cathode catalyst layers at operating temperatures from 80°C to 120°C is quite promising for the development of high-power density with simultaneous high durability.