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Operando X‐Ray Absorption Spectroscopy Shows Iron Oxidation Is Concurrent with Oxygen Evolution in Cobalt–Iron (Oxy)hydroxide Electrocatalysts |
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| Authors: | Dr. Lisa J. Enman Dr. Michaela Burke Stevens Meir Haim Dahan Dr. Michael R. Nellist Prof. Maytal Caspary Toroker Prof. Shannon W. Boettcher |
| Affiliation: | 1. Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR, USA;2. Department of Materials Science & Engineering and The Nancy & Stephen Grand Technion Energy Program, Technion—Israel Institute of Technology, Haifa, Israel |
| 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)OxHy. 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)OxHy. |
| Keywords: | electrocatalysts heterogeneous catalysis oxygen evolution water electrolysis X-ray absorption spectroscopy |