Nano-Scale Simulation of Platinum Particle Dissolution, Re-Deposition, and Transport

Understanding the effect of carbon support morphology on catalyst durability is critical to advancing polymer electrolyte fuel cells (PEFCs) with low platinum (Pt) loading. This paper reports the development of a 3D model to simulate the exchange of Pt between external Pt particles on the carbon support surface and internal Pt particles. The 3D domain consists of a Pt particle embedded in a water-filled micropore, and an external particle covered by an ionomer film. Here, we have developed a computational model to simulate proton and Pt ion transport using the Poisson-Nernst-Planck equations in combination with Pt dissolution and redeposition, and oxidation models. Our results suggest that the external particle increases in a diameter with electrochemical cycling, whereas the particle in the micropore shrinks. In practice, this effect would manifest as an increased amount of Pt in contact with ionomer as well as a reduction in electrochemical surface area (ECSA).