Potential-Dependent Active Moiety of Fe-N-C Catalysts for the Oxygen Reduction Reaction.

Liu, Kang; Fu, Junwei; Luo, Tao; Ni, Ganghai; Li, Hongmei; Zhu, Li; Wang, Ye; Lin, Zhang; Sun, Yifei; Cortés, Emiliano; Liu, Min

Liu, Kang; Fu, Junwei; Luo, Tao; Ni, Ganghai; Li, Hongmei; Zhu, Li; Wang, Ye; Lin, Zhang; Sun, Yifei; Cortés, Emiliano; Liu, Min.

Afiliação

Liu K; School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, P. R. China.
Fu J; Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
Luo T; Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
Ni G; Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
Li H; Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
Zhu L; Hunan Joint International Research Center for Carbon Dioxide Resource Utilization, School of Physics and Electronics, Central South University, Changsha, Hunan 410083, P. R. China.
Wang Y; School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China.
Lin Z; Nanoinstitute Munich, Faculty of Physics, Ludwig Maximilians Universität München, 80539 München, Germany.
Sun Y; School of Energy and Power Engineering, Beihang University, Beijing 100191, China.
Cortés E; School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, P. R. China.
Liu M; School of Energy and Power Engineering, Beihang University, Beijing 100191, China.

J Phys Chem Lett ; 14(15): 3749-3756, 2023 Apr 20.

Article em En | MEDLINE | ID: mdl-37043683

ABSTRACT

ABSTRACT

The real active moiety of Fe-N-C single-atom catalysts (SACs) during the oxygen reduction reaction (ORR) depends on the applied potential. Here, we examine the ORR activity of various SAC active moieties (Fe-N4, Fe-(OH)N4, Fe-(O2)N4, and Fe-(OH2)N4) over a wide potential window ranging from -0.8 to 1.0 V (vs. SHE) using constant potential density functional theory calculations. We show that the ORR activity of the Fe-N4 moiety is hindered by the slow *OH protonation, while the Fe-(OH2)N4 (0.4 V ≤ U ≤ 1.0 V), *O2-assisted Fe-N4 (-0.6 V ≤ U ≤ 0.2 V), and Fe-(OH)N4 (U = -0.8 V) moieties dominate the ORR activity of the Fe-N-C catalysts at different potential windows. These oxygenated species modified the single-atom Fe sites and can promote *OH protonation by regulating the electron occupancy of the Fe 3dz2 (spin-up) and Fe 3dxz (spin-down) orbitals. Overall, our findings provide guidance for understanding the active moieties of SACs.

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Texto completo: 1 Bases de dados: MEDLINE Idioma: En Revista: J Phys Chem Lett Ano de publicação: 2023 Tipo de documento: Article