Surface Interrogation Scanning Electrochemical Microscopy of Ni1-xFexOOH (0 < x < 0.27) Oxygen Evolving Catalyst: Kinetics of the "fast" Iron Sites

Hyun S. Ahn; Allen J. Bard

doi:10.1021/jacs.5b10977

Surface Interrogation Scanning Electrochemical Microscopy of Ni_1-xFe_xOOH (0 < x < 0.27) Oxygen Evolving Catalyst: Kinetics of the "fast" Iron Sites

Hyun S. Ahn, Allen J. Bard

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

239 Citations (Scopus)

Abstract

Nickel-iron mixed metal oxyhydroxides have attracted significant attention as an oxygen evolution reaction (OER) catalyst for solar fuel renewable energy applications. Here, we performed surface-selective and time-dependent redox titrations to directly measure the surface OER kinetics of Ni^IV and Fe^IV in NiOOH, FeOOH, and Ni_1-xFe_xOOH (0 < x < 0.27) electrodes. Most importantly, two types of surface sites exhibiting "fast" and "slow" kinetics were found, where the fraction of "fast" sites in Ni_1-xFe_xOOH matched the iron atom content in the film. This finding provides experimental support to the theory-proposed model of active sites in Ni_1-xFe_xOOH. The OER rate constant of the "fast" site was 1.70 s^-1 per atom.

Original language	English
Pages (from-to)	313-318
Number of pages	6
Journal	Journal of the American Chemical Society
Volume	138
Issue number	1
DOIs	https://doi.org/10.1021/jacs.5b10977
Publication status	Published - 2016 Jan 13

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.

All Science Journal Classification (ASJC) codes

Catalysis
Chemistry(all)
Biochemistry
Colloid and Surface Chemistry

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1021/jacs.5b10977

Cite this

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title = "Surface Interrogation Scanning Electrochemical Microscopy of Ni1-xFexOOH (0 < x < 0.27) Oxygen Evolving Catalyst: Kinetics of the {"}fast{"} Iron Sites",

abstract = "Nickel-iron mixed metal oxyhydroxides have attracted significant attention as an oxygen evolution reaction (OER) catalyst for solar fuel renewable energy applications. Here, we performed surface-selective and time-dependent redox titrations to directly measure the surface OER kinetics of NiIV and FeIV in NiOOH, FeOOH, and Ni1-xFexOOH (0 < x < 0.27) electrodes. Most importantly, two types of surface sites exhibiting {"}fast{"} and {"}slow{"} kinetics were found, where the fraction of {"}fast{"} sites in Ni1-xFexOOH matched the iron atom content in the film. This finding provides experimental support to the theory-proposed model of active sites in Ni1-xFexOOH. The OER rate constant of the {"}fast{"} site was 1.70 s-1 per atom.",

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