Reflection Characteristics of Oxygen Molecule on Ionomer Surface

Abstract

We investigated the scattering phenomena of oxygen molecules on an ionomer surface, which plays a crucial role in oxygen transport in catalyst layers, using molecular dynamics simulations. The probability density functions (PDFs) of the translational energy and scattering angle of scattered oxygen molecules were both analyzed for a wide range of incident condition and water contents. The PDFs of the translational energy depends on the incident energy, but are insensitive to the incident angle and the water content. The PDFs of the scattering angle are independent of the incident conditions and the water contents. Two types of collision behaviors, i.e. single and multiple collisions, were observed in the trajectory calculations. The fraction of multiple collisions and the residence time of oxygen molecules on ionomer surface were also investigated. These results provide an insight into the atomic level dynamics of oxygen scattering on ionomer surface.