Deciphering potential-driven dynamics in Fe-N-C catalysts: <i>ab initio</i> insights into Fe-N switching and spin-state transition.

ABSTRACT: Pyrolyzed Fe-N-C materials are cost-effective alternatives to Pt for the acidic oxygen reduction reaction (ORR), yet the atomic and electronic structures of their active centers remain poorly understood. Operando spectroscopic studies have identified potential-induced reversible Fe-N switching in the FeN _x active centers of D1 type, which provides a unique opportunity to decode their atomic structures, but the mechanism driving this behavior has been elusive. Herein, using constant-potential ab initio molecular dynamics (CP-AIMD), we reveal that pyridinic FeN₄ sites transit reversibly between planar OH*-Fe³⁺N₄ and out-of-plane H₂O*-Fe²⁺N₄ configurations at 0.8 V, mirroring the experimental Fe-

SUBMITTER: Li H 

PROVIDER: S-EPMC12282477 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature