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Mechanism of Nickel–Iron Water Oxidation Electrocatalysts

Zhang, Jibo and Winkler, Jay R. and Gray, Harry B. and Hunter, Bryan M. (2021) Mechanism of Nickel–Iron Water Oxidation Electrocatalysts. Energy and Fuels . ISSN 0887-0624. doi:10.1021/acs.energyfuels.1c02674. (In Press)

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Hotly debated these days is whether nickel or iron is the active site in nickel–iron water oxidation electrocatalysts. We have previously argued that iron is a likely candidate for highly active materials because it can reach high-oxidation (high-ox) states at potentials relevant to water splitting. Here, we further assert that nickel is likely not an active site for water oxidation electrocatalysis in these materials. Our 3-fold argument is supported by electrochemical measurements on rigorously planar electrodes produced by pulsed laser ablation in liquids: (1) nickel cannot achieve high-ox states in aqueous environments at relevant potentials; (2) large steady-state concentrations of metal sites preclude them from being active, thereby indicating that even more oxidizing moieties are critically important; and (3) unlike nickel sites, high-ox iron sites documented experimentally are neither rare nor unreasonably reactive.

Item Type:Article
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URLURL TypeDescription
Winkler, Jay R.0000-0002-4453-9716
Gray, Harry B.0000-0002-7937-7876
Hunter, Bryan M.0000-0001-8559-9304
Additional Information:© 2021 The Authors. Published by American Chemical Society. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) Received 5 August 2021. Published online 23 September 2021. This article is part of the 2021 Pioneers in Energy Research: Vivian Yam special issue. Bryan M. Hunter is a Fellow of the Rowland Institute at Harvard University. The authors thank the Arnold and Mabel Beckman Foundation for support of their work. The authors declare no competing financial interest.
Funding AgencyGrant Number
Rowland InstituteUNSPECIFIED
Arnold and Mabel Beckman FoundationUNSPECIFIED
Subject Keywords:Iron, Radiology, Electrodes, Water oxidation, Nickel
Record Number:CaltechAUTHORS:20211008-224627576
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Official Citation:Mechanism of Nickel–Iron Water Oxidation Electrocatalysts Jibo Zhang, Jay R. Winkler, Harry B. Gray, and Bryan M. Hunter Energy & Fuels Article ASAP DOI: 10.1021/acs.energyfuels.1c02674
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111330
Deposited By: George Porter
Deposited On:11 Oct 2021 23:02
Last Modified:11 Oct 2021 23:02

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