Comparative investigation of nitrogen species in transition metals incorporated carbon catalysts for the oxygen reduction reaction

Abstract

The kinetic influences of transition metals (TMs) in non-platinum group metal (non-PGM) catalysts using ethylenediamine-TM (en-TM) complex are studied for the electro-reduction of oxygen. We exhibit that Ni atoms are inefficiently dispersed, which may influence the N doping as evidenced by XPS and elemental maps. High concentrations of N are attributed to the well-dispersed Co and Fe over the carbon. Electrochemical measurements demonstrate that the ORR on Co@NC and Fe@NC catalysts takes place faster than that on NC and Ni@NC catalysts. The correlation between the quaternary-N concentration of species and the onset potential with respect to TMs is investigated.