Tuning Structural and Electronic Configuration of FeN4 via External S for Enhanced Oxygen Reduction Reaction

• Published in: Energy & environmental materials (Hoboken, N.J.) Vol. 7; no. 2; pp. 93 - n/a
• Main Authors: Li, Shidong, Xia, Lixue, Li, Jiantao, Chen, Zhuo, Zhang, Wei, Zhu, Jiexin, Yu, Ruohan, Liu, Fang, Lee, Sungsik, Zhao, Yan, Zhou, Liang, Mai, Liqiang
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.03.2024; State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China%Chemical Sciences and Engineering Division,Argonne National Laboratory,9700 South Cass Avenue,Lemont,IL 60439,USA%NRC(Nanostructure Research Centre),Wuhan University of Technology,Wuhan 430070,China%X-ray Science Division,Advanced Photon Sources,Argonne National Laboratory,9700 South Cass,Avenue,Lemont,IL 60439,USA%State Key Laboratory of Silicate Materials for Architectures,International School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China; The Institute of Technological Sciences,Wuhan University,Wuhan 430072,China%State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China; Hubei Longzhong Laboratory,Xiangyang 441000,China; Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory,Foshan 528200,China
• Subjects: Catalysts; Chemical reduction; Configurations; Controllability; Coordination; coordination structure; Electrocatalysts; Electron distribution; Electron spin; electronic configuration; Electrons; FeN4 moiety; Oxygen; oxygen reduction reaction; Oxygen reduction reactions; Sulfur; sulfur doping; Valence; FeN4 moiety; sulfur doping; electronic configuration; oxygen reduction reaction; coordination structure
• ISSN: 2575-0356; 2575-0348; 2575-0356
• DOI: 10.1002/eem2.12560

The Fe–N–C material represents an attractive oxygen reduction reaction electrocatalyst, and the FeN4 moiety has been identified as a very competitive catalytic active site. Fine tuning of the coordination structure of FeN4 has an essential impact on the catalytic performance. Herein, we construct a sulfur‐modified Fe–N–C catalyst with controllable local coordination environment, where the Fe is coordinated with four in‐plane N and an axial external S. The external S atom affects not only the electron distribution but also the spin state of Fe in the FeN4 active site. The appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired electrons. With the above characteristics, the adsorption and desorption of the reactants at FeN4 active sites are optimized, thus promoting the oxygen reduction reaction activity. This work explores the key point in electronic configuration and coordination environment tuning of FeN4 through S doping and provides new insight into the construction of M–N–C‐based oxygen reduction reaction catalysts. A S‐modified Fe–N–C oxygen reduction reaction (ORR) catalyst, where the Fe is coordinated with four N and an external S, is designed. The S functionality attracts the electron away from the Fe center, leading to a higher valence state and a changed spin state for Fe in the FeN4 active center, which accelerates the ORR dynamics. Benefiting from the unique coordination environment and optimized electronic structure, the S‐modified Fe–N–C manifests a promoted ORR activity.