Microporous Fe–N4 cataysts derived from biomass aerogel for a high-performance Zn–air battery

Developing inexpensive catalysts with plentiful active sites and high surface area to accelerate the oxygen reduction reaction (ORR) is of great significance for metal–air batteries. Nevertheless, it is still a challenge to balance the content of active sites and the high surface area of catalysts, especially in a versatile and economical way. Herein, a single-atom Fe catalyst was prepared by pyrolyzing biomass aerogels that anchor iron ions through coordination reactions. With the synergistic effect of a large surface area and a high Fe content, the optimized catalyst FeNC-900-8 shows excellent ORR activity and stability. The Zn–air battery with catalyst FeNC-900-8 as the cathode delivers a high peak power density and discharge voltage. This work offers a facile strategy to develop single-atom catalysts with a high surface area and a moderate metal content for high-performance ORRs.