Effect of Hydrogen and Oxygen Partial Pressure on Pt Precipitation within the Membrane of PEMFCs

Pt dissolution and further precipitation within the membrane of proton exchange membrane fuel cells (PEMFCs) was investigated at open-circuit voltage conditions. It was found that the location of Pt precipitation is affected by both H 2 and O 2 permeability through the membrane. A simple model is developed that can predict the location of the Pt precipitation band as a function of H 2 and O 2 partial pressure, which agrees well with measurements. The implications of Pt deposition on membrane chemical degradation are briefly discussed.