Detection of high-valent iron species in alloyed oxidic cobaltates for catalysing the oxygen evolution reaction

Authors

Nancy Li
Ryan G. Hadt
Dugan Hayes, University of Rhode IslandFollow
Lin X. Chen
Daniel G. Nocera

Document Type

Article

Date of Original Version

2021

Department

Chemistry

Abstract

Iron alloying of oxidic cobaltate catalysts results in catalytic activity for oxygen evolution on par with Ni-Fe oxides in base but at much higher alloying compositions. Zero-field ⁵⁷Fe Mössbauer spectroscopy and X-ray absorption spectroscopy (XAS) are able to clearly identify Fe⁴⁺ in mixed-metal Co-Fe oxides. The highest Fe⁴⁺ population is obtained in the 40–60% Fe alloying range, and XAS identifies the ion residing in an octahedral oxide ligand field. The oxygen evolution reaction (OER) activity, as reflected in Tafel analysis of CoFeO_x films in 1 M KOH, tracks the absolute concentration of Fe⁴⁺. The results reported herein suggest an important role for the formation of the Fe⁴⁺ redox state in activating cobaltate OER catalysts at high iron loadings.

Publication Title, e.g., Journal

Nature Communications

Volume

12

Citation/Publisher Attribution

Li, N., Hadt, R.G., Hayes, D. et al. Detection of high-valent iron species in alloyed oxidic cobaltates for catalysing the oxygen evolution reaction. Nat Commun 12, 4218 (2021). https://doi.org/10.1038/s41467-021-24453-6

Available at: https://doi.org/10.1038/s41467-021-24453-6

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.