Electrocatalytic Performance of Fe–N Encapsulated in Hollowly Mesoporous Carbon Microspheres for Oxygen Reduction Reaction and Zn–Air Battery

Isolated single-atom catalysts have attracted tremendous attention for their maximized atom utilization efficiency. However, the rational design of an economical and efficient single-atom catalyst is still confronted with great challenges. In this work, hollow carbon microspheres were constructed by an in situ template method to facilitate the anchoring of iron atoms and optimal porous structure with mesopores centered at around 2–10 nm. The catalyst with the single-atom Fe dispersed on extremely stable hollow carbon microspheres exhibited a better Eon (0.98 V) and E1/2 (0.86 V) than Pt/C in 0.1 M KOH. It also displayed superior long-term durability and an outstanding methanol resistance compared with 20% Pt/C. Meanwhile, the Zn–air battery using the as-obtained catalyst as an oxygen electrocatalyst on an air cathode exhibited superior performance and prolonged operation durability than Pt/C. This design strategy highlighted the tremendous potential of a Fe-based single-atom catalyst for ORR and provided an alternative way for synthesizing other single-atom catalysts with excellent properties suitable for a variety of applications.