A post-synthesis surface reconstructed carbon aerogel as an enhanced oxygen reduction reaction catalyst for zinc–air batteries

Abstract

Being a most promising alternative to platinum-based catalysts for the oxygen reduction reaction, nitrogen-doped carbon materials have been extensively investigated to improve their electro-catalytic activity. In this work, a facile process involving an Fe precursor and annealing in an inert gas atmosphere is applied to the as-prepared carbon aerogel to reconstruct its surface. An optimized Fe-modified carbon aerogel (FCG-2) attains more macropores, more than 4 times higher surface nitrogen content and an elevated proportion of pyridinic nitrogen species. These enhancements result in improved ORR performance of this non-platinum catalyst, positively shifting E_onset by 39 mV and E_1/2 by 14 mV compared to those of the initial carbon aerogel. FCG-2 used as an air cathode catalyst in a Zn–air battery exhibits excellent performance compared with that of a similarly prepared Pt/C cell. Post-synthesis surface reconstruction is feasible in improving the catalytic performance of newly prepared carbon materials.