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

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

291 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
General Chemistry
Biochemistry
Colloid and Surface Chemistry

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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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