Trapping an Iron(VI) Water-Splitting Intermediate in Nonaqueous Media
Abstract
We report in situ spectroscopic measurements in nonaqueous media designed to trap an exceptionally strong oxidant generated electrochemically from an iron-containing nickel layered double hydroxide ([NiFe]-LDH) material. Anodic polarization of this material in acetonitrile produces metal-oxo vibrational spectroscopic signatures along with an extremely narrow near-infrared luminescence peak that strongly indicate that the reactive intermediate is cis-dioxo-iron(VI). Chemical trapping experiments reveal that addition of H_2O to the polarized electrochemical cell produces hydrogen peroxide; and, most importantly, addition of HO– generates oxygen. Repolarization of the electrode restores the iron(VI) spectroscopic features, confirming that the high-valent oxo complex is active in the electrocatalytic water oxidation cycle.
Additional Information
© 2018 Elsevier Inc. Received: December 20, 2017. Revised: January 8, 2018. Accepted: January 11, 2018. Published: February 6, 2018. This work was supported by the NSF CCI Solar Fuels Program ( CHE- 1305124 ) and the Arnold and Mabel Beckman Foundation, with additional support from NSF EAR-1322082 . B.M.H. is a Fellow of the Resnick Sustainability Institute at Caltech. The authors thank Jonas Peters for helpful discussions. Additional data and methods are available in the Supplemental Information. Author Contributions: B.M.H. designed and performed the experiments; N.B.T. collected and analyzed the Mössbauer spectra; A.M.M. synthesized and characterized the materials; G.R.R. assisted with luminescence and Raman electrochemistry; M.G.H. assisted with electrochemistry and IR spectroelectrochemistry; J.R.W. and H.B.G., with the other authors, developed the proposed mechanism. All authors wrote the manuscript. The authors declare no competing interests.Attached Files
Supplemental Material - mmc1.pdf
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Additional details
- Eprint ID
- 84697
- Resolver ID
- CaltechAUTHORS:20180207-065509383
- NSF
- CHE- 1305124
- Arnold and Mabel Beckman Foundation
- NSF
- EAR-1322082
- Resnick Sustainability Institute
- Created
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2018-02-07Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field
- Caltech groups
- CCI Solar Fuels, Resnick Sustainability Institute, Division of Geological and Planetary Sciences