Oxygen reduction by sol derived [Co, N, C, O]-based catalysts for use in proton exchange membrane fuel cells

Two Co oxide sol-derived catalysts, one based on ethylenediamine and one on 1,2-phenylenediamine, were synthesized and examined for their oxygen reduction reaction (ORR) behavior in 0.5 M H2SO4. Supporting the catalyst on carbon powder significantly improved the catalyst performance, while heat-treatment of the carbon-supported catalysts at 650-900degreesC for 2 h under nitrogen dramatically improved its activity and selectivity. The ORR activity was further improved by increasing the concentration of the [Co, N, C, O]-based catalyst on carbon powder to 4% (wt % Co/C), employing the more aromatic 1,2-phenylenediamine ligand, and by using a ligand to Co ratio of 2:1. (C) 2004 The Electrochemical Society.