Numerical Simulation of the Reaction and Mass-Transfer Profiles in the Two-Layer Catalyst of a PEMFC

Abstract

A simple one-dimensional numerical simulation for cathode catalyst layers was conducted to elucidate the signifi-cance of a structure with a gradient in the ionomer content in the cross-plane direction. First, under an assumption of uniform (one-layer) catalysts, equivalent pairs of the effective ionic conductivity and effective gas diffusion coefficient were identified. Next, results with two-layer catalysts were calculated with two pairs of parameters among the equivalent pairs obtained earlier. Comparison of the performance of the two-layer catalysts revealed that ionic conductivity is more important near the PEM, and gas diffusivity is more important near the GDL.