First-Principles Molecular Dynamics Study of Carbon Corrosion in PEFC Catalyst Materials

Carbon corrosion plays an important role in ORR catalyst durability for both Pt-based catalysts as well as Pt group metal-free (PGM-free) catalysts. This corrosion process is attributed to CO2 generation during one of several probable, kinetically controlled electrochemical reactions. Previous relative stability studies considered only thermodynamic formation energy and thus do not include the kinetic nature of the carbon corrosion mechanism. In this manuscript, a model for electron beam damage utilizing first-principles molecular dynamics is applied to the understanding of how defects and surface species may affect the durability and corrosion susceptibility of graphene support structures at the atomic scale. Based on the outcomes of these studies, the calculated knockon displacement threshold energy is hypothesized to be a computationally accessible durability descriptor sensitive to kinetics of C removal and local atomic structure.