High-performance carbon alloy cathode catalysts for fuel cells prepared from polymer precursor

Abstract

The polymer electrolyte fuel cell (PEFC) is a promising, clean power source for transportation and residential applications with high efficiency, low operating temperature, and reduced CO 2 emissions. Conventionally, platinum is used as a cathode electrocatalyst for the slow oxygen reduction reaction (ORR), but it is too expensive to provide a viable alternative to conventional energy sources. For practical use of PEFCs, alternative low-cost, platinum-free cathode catalysts with high power loads are necessary. Carbon based materials doped with nitrogen are receiving much attention as catalysts, owing to their relatively high ORR activities. We have also been developing our own electrochemically active nitrogen-containing carbon materials by pyrolyzing nitrogen-containing polymer. These inexpensive, carbon-based catalysts, containing hetero-atoms such as boron or nitrogen, are known as carbon alloy catalysts (CACs). We have studied the pyrolyzing process very carefully to optimize the catalyst preparation protocol. The nitrogen content is essential in obtaining highly active carbon alloy catalysts. Electrocatalytic activity for ORR in our carbon alloy catalysts has been investigated via fuel cell testing, results show good open circuit voltages of 1.01-1.03 V, and extremely promising current densities. The maximum output is 0.56 Won-2. To our knowledge, the performance of this fuel cell is unsurpassed when compared to other state-of-the-art non-precious metal cathode catalysts. © 2011, The Society of Polymer Science, Japan.