Nanoporous Carbon-Supported Fe/Co-N Electrocatalyst for Oxygen Reduction Reaction in PEM Fuel Cells Ja-Yeon Choi, Ryan Hsu, Zhongwei Chen Department of Chemical Engineering, Waterloo Institute for Nanotechnology, Waterloo Institute for Sustainable Energy, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 As a substitute for high-cost platinum based catalysts, nonprecious catalysts for the oxygen reduction reaction were synthesized by deposition of Fe/Co-N composite onto two different nanoporous carbon supports, Ketjen Black EC300J and EC600JD, using ethylenediamine as a nitrogen precursor. Rotating ring disk electrode measurements were used to investigate the ORR activity, and the results obtained from EC600JD based catalyst, showed improved onset and half-wave potentials and superior selectivity than that of the EC300J. Similarly, the catalyst showed good performance in the hydrogen-oxygen PEMFC, being able to produce 0.37 A/cm2 with a maximum power density of 0.44 W/cm2 at a cell voltage of 0.6 V. A fuel cell life test at a voltage of 0.40 V demonstrated promising stability up to 100 h. These results suggest that a higher pore volume and surface area of the carbon support could lead to higher nitrogen content, providing more active sites for ORR. Introduction Polymer electrolyte membrane (PEM) fuel cells have been receiving lots of attention as a sustainable power source for transport, stationary, and portable applications due to their high efficiency and low emissions (1, 2). Though tremendous progress has been made in the past decades, the slow kinetics of the oxygen reduction reaction (ORR) at the cathode of PEM fuel cells are still one of the primary aspects limiting its performance. To date, the best materials for the catalysis of ORR are platinum-based; however, they suffer from slow reduction kinetics and high cost, which hinders the large-scale commercialization of low-temperature fuel cells (3-5). As a substitute for platinum, the development of nonprecious metal catalysts (NPMCs) with high activity and practical durability for ORR has been viewed as the long-term solution to reduce the cost (6). Much effort has been devoted to the development of NPMCs in recent years. Nonprecious metal/polymer nanocomposite catalysts with different nitrogen-containing precursors have demonstrated high catalytic activity toward ORR. Among these catalysts, NPMCs with high ORR activity synthesized by modification of the carbon support with porphyrin, polypyrrole, polyaniline, or ethylenediamine (EDA) as a nitrogen precursor has received a lot of attention (7-13). However, most reports of NPMCs have not exceeded the performance of commercial platinum catalysts in PEM fuel cells in both activity and stability. ECS Transactions, 28 (23) 101-112 (2010) 10.1149/1.3502342 ©The Electrochemical Society 101 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 52.70.26.25 Downloaded on 2017-10-25 to IP