Polymer electrolyte membrane (PEM) fuel cells are being developed for a variety of applications such as automotive power.
The cathode catalyst is commonly based on Pt alloyed with a second metal. Continued advances in Pt-based bimetallic electrocatalysts for the oxygen reduction reaction (ORR) in PEM fuel cells requires a greater understanding of how segregation of the components affects the activity of the materials and then a further understanding of the stability and degradation of the structures. In this project, sponsored by the Johnson Matthey Technology Centre, we are using a variety of electrochemical, structural (XRD and TEM), and spectroscopic (XAS and XPS) techniques to explore the structures that develop during electrochemical aging of Pt3X/C electrocatalysts.