Effects of graphite oxide additions on the oxygen reduction reaction activity of a carbon alloy catalyst for a polymer electrolyte fuel cell cathode

Abstract

The effects of graphite oxide (GO) additions on the oxygen reduction reaction (ORR) activity of carbon alloy catalysts were examined in order to develop high performance cathode catalysts for polymer electrolyte fuel cell. Different amounts of GO were mixed with a carbon alloy precursor consisting of phenolic resin and phthalocyanine iron, followed by carbonization at 800 °C. Thermogravimetry revealed that the GO addition changed the carbonization behavior of the precursor. The formation of a nanoshell structure was observed under TEM for the carbons derived from precursors containing less than 50% GO. The ORR activities of the obtained carbons in 0.5 M H 2 SO 4 varied with the GO content showing a maximum at 40% GO. A similar trend was obtained for the relation between the N/C atomic ratio determined by XPS and the GO content; the contribution of edge nitrogen species such as pyrrole/pyridone and pyridine types to the ORR activity was suggested. The results indicate that the GO addition to the carbon alloy precursors improved the ORR activity, and that it was caused by the introduction of edge nitrogen species. [TANSO 2014 (No. 265) 159–164.]