Post-synthesis Surface Reconstructed Carbon Aerogel as Enhanced Oxygen Reduction Reaction Catalyst for Zinc-air Battery

Being a most promising alternative to platinum-based catalysts for oxygen reduction reaction, nitrogen-doped carbon materials have been extensively investigated to improve their electro-catalytic activity. In this work, a facile process involving Fe precursor and annealing in an inert gas atmosphere is applied to 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 elevated proportion of pyridinic nitrogen species. These enhancements result in improved ORR performance of this non-platinum catalyst, positively shifting Eonset by 39 mV and E1/2 by 14 mV compared to 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 catalytic performance of newly prepared carbon materials. Keywords: Surface reconstruction; carbon aerogel; iron; nitrogen-doped; zinc-air battery.