Minimizing the quantity of Pt group metals used in polymer membrane fuel cells (PEMFCs) is one of the remaining grand challenges for fuel cell commercialization. Tremendous progress has been achieved over the last two decades in decreasing the Pt loading required for efficient fuel cell performance. Unfortunately, the fluctuations in the price of Pt represent a substantial barrier to the economics of widespread fuel cell use. Durability and impurity tolerance are also challenges that are tightly coupled to fuel cell Pt electrode loading. Traditional approaches to decreasing the amount of Pt required for good performance include: (1) Increasing mass activity by decreasing Pt particle size by supporting on carbon
(2) Alloy formulation Pt-Co, Pt-Cr alloys to improve mass activity
(3) Increasing Pt utilization by optimization of electronic and ionic contact of the Pt particles
(4) Improving conductivity of the electronic and ionic conducting constituents of the membrane electrode assembly
and (5) Improving reactant to and product mass transport away from the electroactive sites. Recent novel approaches include the nanoengineering of core shell catalysts and Pt particles of unusual geometries such as nanowires/whiskers. The success of the aforementioned approaches has been great
however further advances using such approaches have been hampered by a lack of underlining scientific understanding of the catalyst activity, particle growth mechanisms, and optimization strategies for designing composite electrodes The objectives of this report are: (1) Development of durable, high mass activity Platinum Group Metal (PGM) cathode catalysts-enabling lower cost fuel cells
(2) Elucidation of the fundamental relationships between PGM catalyst shape, particle size and activity to help design better catalysts
(3) Optimization of the cathode electrode layer to maximize the performance of PGM catalysts-improving fuel cell performance and lowering cost
(4) Understanding the performance degradation mechanisms of high mass activity cathode catalysts-provide insights to better catalyst design
and (5) Development and testing of fuel cells using ultra-low loading high activity PGM catalysts-validation of advanced concepts.