Unveiling the in Situ Generation of a Monovalent Fe(I) Site in the Single-Fe-Atom Catalyst for Electrochemical CO2 Reduction

Xuning Li, Yaqiong Zeng, Ching Wei Tung, Ying Rui Lu, Sambath Baskaran, Sung Fu Hung, Shifu Wang, Cong Qiao Xu, Junhu Wang, Ting Shan Chan, Hao Ming Chen, Jianchao Jiang, Qi Yu, Yanqiang Huang, Jun Li, Tao Zhang, Bin Liu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Atomically dispersed single-atom catalysts are among the most attractive electrocatalysts for the CO2 reduction reaction (CRR). To elucidate the origin of the exceptional activity of atomically dispersed Fe-N-C catalyst in CRR, we have performed operando 57Fe Mössbauer spectroscopic studies on a model single-Fe-atom catalyst with a well-defined N coordination environment. Combining with operando X-ray absorption spectroscopy, the in situ-generated four pyrrolic nitrogen atom-coordinated low-spin Fe(I) (LS FeIN4) featuring monovalent iron is identified as the reactive center for the conversion of CO2 to CO. Furthermore, density functional theory calculations reveal that the optimal binding strength of CO2 to the LS FeIN4 site, with strong orbital interactions between the singly occupied dz2 orbital of the Fe(I) site and the singly occupied π∗ orbital of [COOH] fragment, is the key factor for the excellent CRR performance.

Original languageEnglish
Pages (from-to)7292-7301
Number of pages10
JournalACS Catalysis
Volume11
Issue number12
DOIs
StatePublished - 18 Jun 2021

Keywords

  • electrochemistry
  • Mössbauer spectroscopy
  • operando
  • reaction mechanism
  • single-atom catalyst

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