Journal of the American Chemical Society· 2015Q1
Identification of Highly Active Fe Sites in (Ni,Fe)OOH for Electrocatalytic Water Splitting
- 2,668citations
- Q1SCImago
- 2015year
Short summary
Fe(3+) sites in mixed (Ni,Fe)oxyhydroxides (Ni(1-x)Fe(x)OOH) are responsible for a 500-fold enhancement in oxygen evolution reaction (OER) activity compared to pure Ni or Fe compounds.
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Key points
- Fe(3+) in (Ni,Fe)oxyhydroxides is the active site for the oxygen evolution reaction (OER).
- A 500-fold OER activity enhancement is observed in mixed (Ni,Fe)oxyhydroxides over pure Ni or Fe compounds.
- Fe(3+) occupies octahedral sites with short Fe-O bond distances, influenced by adjacent [NiO6] octahedra.
- Computational studies show these Fe sites have near-optimal adsorption energies for OER intermediates and low overpotentials.
AI-generated from the title and abstract; the full text is not read.
Abstract
Highly active catalysts for the oxygen evolution reaction (OER) are required for the development of photoelectrochemical devices that generate hydrogen efficiently from water using solar energy. Here, we identify the origin of a 500-fold OER activity enhancement that can be achieved with mixed (Ni,Fe)oxyhydroxides (Ni(1-x)Fe(x)OOH) over their pure Ni and Fe parent compounds, resulting in one of the most active currently known OER catalysts in alkaline electrolyte. Operando X-ray absorption spectroscopy (XAS) using high energy resolution fluorescence detection (HERFD) reveals that Fe(3+) in Ni(1-x)Fe(x)OOH occupies octahedral sites with unusually short Fe-O bond distances, induced by edge-sharing with surrounding [NiO6] octahedra. Using computational methods, we establish that this structural motif results in near optimal adsorption energies of OER intermediates and low overpotentials at Fe sites. By contrast, Ni sites in Ni(1-x)Fe(x)OOH are not active sites for the oxidation of water.
The authors' abstract, as published at the source. Journal of the American Chemical Society, 2015 · DOI ↗
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Field: Renewable Energy, Sustainability and the Environment
Renewable Energy, Sustainability and the EnvironmentEnergy