Investigation of non-platinum cathode catalysts for direct borohydride fuel cells

Non-platinum electrocatalysts, i.e. iron tetramethoxyphenyl porphyrin (FeTMPP), silver and nickel, were evaluated regarding their ORR performances in alkaline media in half-cells and in alkaline electrolyte borohydride fuel cells. The FeTMPP cathode showed superior performances to those observed using the silver and nickel cathodes, e.g. a current density of -32.2 mA cm(-2) at -0.8 V vs. Hg/HgO, an exchange current density of 7.3 x 10(-8) mA cm(-2) and power densities of up to 65.3 MW cm(-2). The difference in performance can be attributed to variations in activity towards oxygen reduction reaction and in borohydride tolerance among the cathodes. The non-platinum cathodes were compared to a platinum cathode. (c) 2006 Elsevier B.V. All rights reserved.