Synergistic Coupling of Anionic Ligands to Optimize the Electronic and Catalytic Properties of Metal-Organic Framework-Converted Oxygen-Evolving Catalysts

Wenhui He, Hui Min Gao, Ran Shimoni, Zhong Yuan Lu, Idan Hod

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Multimetallic oxygen evolution reaction (OER) electrocatalysts have recently gained significant attention due to their excellent intrinsic activity resulting from the synergistic interplay between multiple metal sites. However, in these multimetallic catalyst systems, the function of their bridging anionic ligands (e.g., O2-, S2-, and P3-/PO43-) is rarely investigated, partially due to the lack of an ideal material model system. Herein, by combining a careful electrochemical conversion of metal-organic framework (MOF) precursors with low-temperature phosphorization processes, we designed a series of NiFe-based model catalysts as a proof-of-concept platform to identify the roles of different anionic ligands in tuning the redox and electronic properties of metal sites. Our experimental and theoretical results reveal that ligands having varying electron-withdrawing/-donating ability can modulate not only the electron density of Ni2+/Fe3+ centers but also the electron transfer efficiency from Ni2+ to neighboring Fe3+ sites. Importantly, synergistically coupled ligands (e.g., S2- and PO43-) with complementary electronic properties help to optimize the chemical environments of the Ni2+/Fe3+ centers (even upon partial catalyst surface reconstruction to NiFe oxyhydroxide), thus giving rise to a remarkable OER activity. These insights open new avenues for developing highly active multimetallic OER electrocatalysts.

Original languageEnglish
Pages (from-to)2138-2148
Number of pages11
JournalACS Applied Energy Materials
Volume2
Issue number3
DOIs
StatePublished - 25 Mar 2019

Keywords

  • anionic ligands
  • electrocatalysis
  • metal redox
  • metal-organic frameworks
  • oxygen evolution reaction

Fingerprint

Dive into the research topics of 'Synergistic Coupling of Anionic Ligands to Optimize the Electronic and Catalytic Properties of Metal-Organic Framework-Converted Oxygen-Evolving Catalysts'. Together they form a unique fingerprint.

Cite this