Mn Single-Atom Tuning Fe-N-C Catalyst Enables Highly Efficient and Durable Oxygen Electrocatalysis and Zinc–Air Batteries

Fe-N-C catalyst is one of most promising candidates for oxygen electrocatalysis reaction in zinc-air batteries (ZABs), but achieving sustained high activity is still a challenging issue. Herein, we demonstrate that introducing Mn single atoms into Fe-N-C (Mn₁@Fe-N-C/CNTs) enables the realization of highly efficient and durable oxygen electrocatalysis performance and application in ZABs. Multiple characterizations confirm that Mn₁@Fe-N-C/CNTs is equipped with Mn-N₂O₂ and Fe-N₄ sites and Fe nanoparticles. The Mn-N₂O₂ sites not only tune the electron structure of Fe-N_x sites to enhance intrinsic activity, but also scavenge the attack of radicals from Fe-N_x sites for improvement in ORR durability. As a result, Mn₁@Fe-N-C/CNTs exhibits enhanced ORR performance to traditional Fe-N-C catalysts with high E_1/2 of 0.89 V vs reversible hydrogen electrode (RHE) and maintains ORR activity after 15 000 CV. Impressively, Mn₁@Fe-N-C/CNTs also presents excellent OER activity and the difference (ΔE) between E_1/2 of ORR and OER potential at 10 mA cm^-2 (E_j10) is only 0.59 V, outperforming most reported catalysts. In addition, the maintainable bifunctional activity of Mn₁@Fe-N-C/CNTs is demonstrated in ZABs with almost unchanged cycle voltage efficiency up to 200 h. This work highlights the critical role of Mn single atoms in enhancing ORR activity and stability, promoting the development of advanced catalysts.