Exploring Fe‐N_<i>x</i> for Peroxide Reduction: Template‐Free Synthesis of Fe‐N_<i>x</i> Traumatized Mesoporous Carbon Nanotubes as an ORR Catalyst in Acidic and Alkaline Solutions

Abstract

Fe-based electrocatalysts are elegant due to their better performance towards the oxygen reduction reaction. Nevertheless, they commonly contain different moieties, for example Fe-N_x , Fe, Fe₃ C and N-doped carbon, primarily the debatable assistance of these components towards ORR electrocatalysis, specifically for intermediate peroxide reduction reactions (PRR). In this paper, to explore the role of Fe-N_x centres for PRR, a Fe-N-C electrocatalyst rooted in nitrogen-doped carbon nanotubes with mesoporous structures was synthesized from a Fe/Zn-dicyanoimidazolate framework. The use of dicyanoimidazole coordinated with iron can introduce the Fe-N_x active sites as well as directional N-doped carbon nanotubes, which is good for enhancing electronic conductance of the catalyst. The attained electrocatalyst shows tremendous enactment to ORR, being comparable to the activity of Pt/C in acidic and better in alkaline electrolytes. This study also reveals that Fe-N_x active centres are responsible for less H₂ O₂ production. Though the Fe-N_x moieties and Fe₃ C/Fe particles encapsulated N-doped carbon, both are active centres for ORR, however, Fe-N_x sites are more active than others for peroxide reduction reaction. These perceptions suggest rational methodologies for more active and consequently further durable Fe-N-C catalysts.