Recent developments in Pt-Co catalysts for proton-exchange membrane fuel cells

Development of Pt-based oxygen reduction reaction catalysts with high efficiency and high durability is central to the application of proton-exchange membrane fuel cell systems. Pt-Co bimetallic catalysts have drawn extensive attention owing to their capability of delivering high performance and long lifetime for fuel cell applications including light-duty and heavy-duty vehicles. However, further improvements in durability and performance are needed to meet market requirements. To fully exploit the potential of Pt-Co catalysts, new insights into the relationship between catalyst properties and fuel cell performance and durability are needed, and more effective methods to tailor the features of Pt-Co catalysts need to be developed. This review provides a summary and perspective on recent efforts, including work on customizing the Pt shell and Pt:Co ratio, tailoring the crystal structure, and improving carbon support properties, with a particular emphasis on mechanisms leading to enhancement of mass activity, power density, and durability in membrane electrode assembly testing.