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

Research output: Contribution to journalArticle

102 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 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.

Original languageEnglish
Pages (from-to)313-318
Number of pages6
JournalJournal of the American Chemical Society
Volume138
Issue number1
DOIs
Publication statusPublished - 2016 Jan 13

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Electrochemical Scanning Microscopy
Microscopic examination
Iron
Oxygen
Scanning
Catalysts
Kinetics
Renewable Energy
Atoms
Nickel
Titration
Reaction kinetics
Oxidation-Reduction
Reaction rates
Rate constants
Catalytic Domain
Electrodes
Metals

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

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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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AB - 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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