Identification of highly active Fe sites in (Ni,Fe)OOH for electrocatalytic water splitting

Daniel Friebel*, Mary W. Louie, Michal Bajdich, Kai E. Sanwald, Yun Cai, Anna M. Wise, Mu Jeng Cheng, Dimosthenis Sokaras, Tsu Chien Weng, Roberto Alonso-Mori, Ryan C. Davis, John R. Bargar, Jens K. Nørskov, Anders Nilsson, Alexis T. Bell

*Corresponding author for this work

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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 (Ni1-xFexOOH) 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 Fe3+ in Ni1-xFexOOH 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 Ni1-xFexOOH are not active sites for the oxidation of water. (Graph Presented).

Original languageEnglish
JournalJournal of the American Chemical Society
Issue number3
Pages (from-to)1305-1313
Number of pages9
Publication statusPublished - 2015
Externally publishedYes

Cite this

Friebel, D., Louie, M. W., Bajdich, M., Sanwald, K. E., Cai, Y., Wise, A. M., Cheng, M. J., Sokaras, D., Weng, T. C., Alonso-Mori, R., Davis, R. C., Bargar, J. R., Nørskov, J. K., Nilsson, A., & Bell, A. T. (2015). Identification of highly active Fe sites in (Ni,Fe)OOH for electrocatalytic water splitting. Journal of the American Chemical Society, 137(3), 1305-1313.