This Small Business Innovation Research (SBIR) Phase II project will develop platinum-transition metal alloy catalysts that are supported on high area carbon for oxygen cathodes in proton exchange membrane fuel cells. The Phase II project will build on the success of Phase I by optimizing the alloy composition and particle size of supported Platinum (Pt) alloy catalysts for efficient oxygen reduction. Low temperature synthesis methods allow T/J Technologies to produce supported Pt alloys with minimal Pt aggregation. Alloy compositions that reduce the over potential toward oxygen reduction by >50 mV versus Pt alone and will be produced with particles sizes (3-5 nm) that maximize Pt utilization and oxygen reduction efficiency. Performance will be demonstrated in half-cell and full fuel cell experiments. Catalysts resulting from this project will enable PEM fuel cells to operate more efficiently.<br/><br/>The potential commercial applications from this project would be improved oxygen reduction catalysts for proton exchange membrane fuel cells for vehicle propulsion and kilowatt-scale off-grid electric power generation. These are potentially large markets with beneficial impacts on energy efficiency, international competitiveness, and emissions reductions.