Operando X-Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt-Iron (Oxy)hydroxide Electrocatalysts.

Enman, Lisa J; Stevens, Michaela Burke; Dahan, Meir Haim; Nellist, Michael R; Toroker, Maytal Caspary; Boettcher, Shannon W.

Enman LJ; Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR, 97403, USA.
Stevens MB; Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR, 97403, USA.
Dahan MH; Department of Materials Science & Engineering and The Nancy & Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa, 3200003, Israel.
Nellist MR; Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR, 97403, USA.
Toroker MC; Department of Materials Science & Engineering and The Nancy & Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa, 3200003, Israel.
Boettcher SW; Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR, 97403, USA.

Angew Chem Int Ed Engl ; 57(39): 12840-12844, 2018 Sep 24.

Article en En | MEDLINE | ID: mdl-30112793

ABSTRACT

Iron cations are essential for the high activity of nickel and cobalt-based (oxy)hydroxides for the oxygen evolution reaction, but the role of iron in the catalytic mechanism remains under active investigation. Operando X-ray absorption spectroscopy and density functional theory calculations are used to demonstrate partial Fe oxidation and a shortening of the Fe-O bond length during oxygen evolution on Co(Fe)Ox Hy . Cobalt oxidation during oxygen evolution is only observed in the absence of iron. These results demonstrate a different mechanism for water oxidation in the presence and absence of iron and support the hypothesis that oxidized iron species are involved in water-oxidation catalysis on Co(Fe)Ox Hy .

Palabras clave

X-ray absorption spectroscopy; electrocatalysts; heterogeneous catalysis; oxygen evolution; water electrolysis

Texto completo: 1 Banco de datos: MEDLINE Idioma: En Año: 2018 Tipo del documento: Article