Details

Autor(en) / Beteiligte

• Dionigi, Fabio
• Zeng, Zhenhua
• Sinev, Ilya
• Merzdorf, Thomas
• Deshpande, Siddharth
• Lopez, Miguel Bernal
• Kunze, Sebastian
• Zegkinoglou, Ioannis
• Sarodnik, Hannes
• Fan, Dingxin
• Bergmann, Arno
• Drnec, Jakub
• Araujo, Jorge Ferreira de
• Gliech, Manuel
• Teschner, Detre
• Zhu, Jing
• Li, Wei-Xue
• Greeley, Jeffrey
• Cuenya, Beatriz Roldan
• Strasser, Peter

Titel

In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution

Ist Teil von

• Nature communications, 2020-05, Vol.11 (1), p.2522-2522, Article 2522

Ort / Verlag

England: Nature Publishing Group

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• NiFe and CoFe (MFe) layered double hydroxides (LDHs) are among the most active electrocatalysts for the alkaline oxygen evolution reaction (OER). Herein, we combine electrochemical measurements, operando X-ray scattering and absorption spectroscopy, and density functional theory (DFT) calculations to elucidate the catalytically active phase, reaction center and the OER mechanism. We provide the first direct atomic-scale evidence that, under applied anodic potentials, MFe LDHs oxidize from as-prepared α-phases to activated γ-phases. The OER-active γ-phases are characterized by about 8% contraction of the lattice spacing and switching of the intercalated ions. DFT calculations reveal that the OER proceeds via a Mars van Krevelen mechanism. The flexible electronic structure of the surface Fe sites, and their synergy with nearest-neighbor M sites through formation of O-bridged Fe-M reaction centers, stabilize OER intermediates that are unfavorable on pure M-M centers and single Fe sites, fundamentally accounting for the high catalytic activity of MFe LDHs.