Catalyst Development Needs and Pathways for Automotive PEM Fuel Cells

Abstract

Mass production of cost-competitive fuel cell vehicles will require oxygen reduction catalysts with 4 times the mass activity of current state-of-the-art platinum/carbon materials. The catalysts must maintain this high activity through the aggressive automotive duty cycle. Pt-alloy catalysts have to date given at least half the required activity gain, and the activity advantages of alloys vs. pure Pt are maintained in PEMFCs even under low-humidification conditions. Alloys show durability advantages, but sometimes- seen losses of specific activity must be understood. Consideration of the mechanisms whereby alloys enhance oxygen reduction activity has led to literature reports of several promising pathways to 4x Pt activity, primarily through control of catalyst particle surface structure and subsurface layer composition. A critical topic for upcoming research will be to determine whether activities enhanced by such structural control can be made durable against realistic drive cycles.