Unraveling the Oxygen‐Reduction Sites in Graphitic‐Carbon Co–N–C‐Type Electrocatalysts Prepared by Single‐Precursor Pyrolysis

摘要: Metal- and nitrogen-doped carbon-based hybrid materials (M–N–C) are widely regarded as promising alternative to platinum for catalyzing the oxygen-reduction reaction (ORR) in fuel-cell cathodes. The two important steps involved preparation of these catalysts acid washing a second heat treatment pyrolyzed mixture made carbon, nitrogen, metal precursors (M). We have explored detail changes induced by post-treatment on structure, composition, activity new prepared prolonged pyrolysis single well-defined organometallic precursor. marginal increase nitrogen content, apparent BET surface area, porosity, defects, higher degree graphitization positively contribute substantial improvement ORR post-treated alkaline solution, whereas this procedure is found weaker influence solution. findings from study suggest that both free nitrogen-coordinated sites, specifically, “Co2N” which present catalyst bulk protected graphitic carbon layer, most likely active sites Co–N–C catalysts. Based experimental results, we propose model will assist improving understanding plausible functioning