Studies on Co-based catalysts supported on modified carbon substrates for PEMFC cathodes

Cobalt based non-precious metal catalysts were prepared by supporting cobalt-ethylene diamine complex on carbon followed by a heat treatment at elevated temperatures (800 °C). Surface oxygen groups on carbon were introduced with HNO3 oxidation. Co catalysts supported on oxidized carbon showed improved activity and selectivity towards four-electron reduction of molecular oxygen. Quinone groups introduced by nitric acid treatment, in addition to increasing the dispersion of the chelate complexes, play a role in forming the active site for oxygen reduction.