Development of Ir-based and Rh-based catalyst electrodes for PEM fuel cell applications

In this work, we have used Ir-4(CO)(12) and Rh-6(CO)(16) as precursors to obtain catalysts by pyrolysis in H-2 and by thermolysis in o-dichlorobenzene, respectively. They can perform both the oxygen reduction and the hydrogen oxidation reaction (ORR and NOR, respectively), the latter even in the presence of CO. However, the Ir-y(H-2) catalyst cannot perform the ORR in the presence of methanol. Their evaluation as anodes in a PEMFC, in the absence and presence of CO, was carried out using a Fuel Cell Test System designed and built in our group. The polarization curves showed that the performance of Ir-y(H-2) is not far from that exhibited by platinum with H-2; when a H-2/0.5% CO mixture was used, the cells with the Ir-y(H-2) or Rh-z(o-DCB) electrodes maintained their potential within acceptable values, unlike that with platinum, which completely lost its power. On the other hand, the performance of Ir-based and Rh-based catalysts as cathodes, was less effective than that exhibited by platinum. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.