Investigating the Performance of Catalyst Layer Micro-Structures with Different Platinum Loadings

Abstract

In this study a four-phase micro-structure of a PEFC catalyst layer was reconstructed by randomly placing overlapping spheres for each solid catalyst phase. The micro-structure was mirrored to make a 1 µm micro-structure. A body-fit computational mesh was produced for the reconstructed micro-structure in OpenFOAM. Associated conservation equations were solved within all the phases with electrochemical reaction as the boundary condition at the interface between ionomer and platinum phases. The study is focused on the platinum loading of CL. The polarization curves of the micro-structure performance have been compared for different platinum loadings. This paper gives increased insight into the relatively greater losses at decreased platinum loadings.

Influence of catalyst structure on PEM fuel cell performance – A numerical investigation

“…1. Each of these phases play an important role in the key processes occurring within the entire fuel cell, starting from the diffusion of gases through pores and in the ionomer film; from the water absorption by the ionomer or water diffusion back to the pore; from proton and electron transfer through the ionomer film and carbon/platinum, respectively; up to the heat transfer from the reaction site towards the gas channel [4]. Some critical factors, such as: mass transport resistance caused by the ionomer and liquid water films surrounding the catalyst particles, Pt loading, Pt and carbon particle sizes, ionomer volume fraction and CL porosity, must be considered when the PEM fuel cell performance and durability are being evaluated [5][6][7][8].…”