Tailoring Oxygen Reduction Reaction Kinetics of Fe-N-C catalyst via Spin Manipulation for Efficient Zinc-Air Batteries.

The interaction between oxygen species and metal sites of various orbitals exhibits intimate correlation with the oxygen reduction reaction (ORR) kinetics. Herein, we represent a new approach for boosting the inherent ORR activity of atomically dispersed Fe-N-C matrix by implanting Fe atomic clusters nearby. Our as-prepared catalyst delivers excellent ORR activity with half-wave potentials of 0.78 V and 0.90 V in acidic and alkaline solutions, respectively. The decent ORR activity could also be validated from the high-performance rechargeable Zn-air battery. The experiments and density functional theory calculations reveal that the electron spin-state of monodispersed Fe active sites is transferred from the low spin (LS, t 2g 6 e g 0 ) to the medium spin (MS, t 2g 5 e g 1 ) due to the involvement of Fe atomic clusters, leading to the spin electron filling in σ∗ orbit, by which it favors OH - desorption and in turn boosts the reaction kinetics of the rate-determining step. This work paves a solid way for rational design of high-performance Fe-based single atom catalysts through spin manipulation. This article is protected by copyright. All rights reserved.