Molecular Dynamics Analysis of the Scattering Phenomena of Oxygen Molecules on an Ionomer Surface in Catalyst Layer of Fuel Cell

The purpose of this study is to clarify the effect of surface diffusion, which is the behavior of gas molecules on ionomer thin films, on the transport properties of oxygen in fuel cell catalyst layers. To this end, the direct simulation Monte Carlo (DSMC) and molecular dynamics (MD) methods were used in our simulations. The results of the DSMC method showed that the overall transport is strongly affected by the behavior of surface diffusion. It was found that the diffuse reflection model for surface diffusion used in the DSMC method has room for improvement as the MD results show a different trend that oxygen molecules tend to reflect in the direction of travel.