Trapping an Iron(VI) Water-Splitting Intermediate in Nonaqueous Media

Overview

Title: 

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 H2O 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.

Authors: 

Hunter, Bryan M.; Thompson, Niklas B.; Müller, Astrid M.; Rossman, George R.; Hill, Michael G.; Winkler, Jay R.; Gray, Harry B.

DOI: 

Journal: 

Joule

Year: 

2018

Catalysis

Catalysis: 

Indicate the type of catalyst: 

Catalyst Name/Chemical Formula: 

  • [Ni-Fe]-LDH

Catalyst Keyword(s): 

Nickel-Iron
Nickel
Iron
Ni-Fe

Description of catalysis: 

Reaction type: 

Reactants: 

Reactant: 

Proposed mechanism: 

Surface Area Enhancement: 

Referenced to Fc+/Fc?: 

No

Is a proton source used?: 

No

Is Bulk Electrolysis reported?: 

No

Active Wavelength Range: 

Unit: 

ASTM Illumination Conditions: 

No

Is the system PV-driven?: 

No

Active Wavelength Range: 

Unit: 

Catalyst and photoactive species are the same: 

Is the photoactive species molecular?: 

No

Anode Material Photoactive: 

Cathode Material Photoactive: 

ASTM Illumination Conditions: 

No

Keywords: 

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