Fe, N-doped graphene-wrapped carbon black nanoparticles as highly efficient catalyst towards oxygen reduction reaction.

• Fe, N-doped graphene wrapped on nanoparticles of carbon black. • Hierarchically microporous structure was constructed. • Graphitic N sites with more ORR activity were preferentially formed. • The catalyst exhibits an excellent ORR activity in alkaline electrolyte. Fe, N-doped graphene-like carbon layers-wrapped carbon black composite (L-Fe-AD+C) was developed by pyrolyzing the mixture of Fe-adenine precursors and conductive carbon black as an efficient catalyst to oxygen reduction reaction (ORR). Graphitic N sites with more ORR activity are preferentially formed due to the facilitation of metallic Fe. Furthermore, graphene-like ultra-thin networks wrapped around nanoparticles of carbon black greatly increase the exposure of active sites and construct continuous diffusion channels favorable for the transfer of substances. As a result, the as-prepared L-Fe-AD+C exhibits an excellent ORR activity in alkaline electrolyte with a high half wave potential (0.88 V), and superior selectivity together with admirable stability, which are comparable to those of the benchmark Pt/C catalyst. More encouragingly, the L-Fe-AD+C can serve as an efficient cathode catalyst in a zinc-air battery, which reaches a peak power density of 221 mW cm−2 approximating to that of Pt/C catalyst (236 mW cm−2). The battery also shows a steady discharge voltage plateau of 1.26 V and specific capacity of 799 mAh g−1 at a discharge current density of 10 mA cm−2. The results suggest the considerable potential of the L-Fe-AD+C catalyst to replace precious metal catalysts. [ABSTRACT FROM AUTHOR]