Abstract

The active site for electrocatalytic water oxidation on the highly active iron(Fe)-doped β-nickel oxyhydroxide (β-NiOOH) electrocatalyst is hotly debated. Here we characterize the oxygen evolution reaction (OER) activity of an unexplored facet of this material with first-principles quantum mechanics. We show that molecular-like 4-fold-lattice-oxygen-coordinated metal sites on the (1211) surface may very well be the key active sites in the electrocatalysis. The predicted OER overpotential (η OER ) for a Fe-centered pathway is reduced by 0.34 V relative to a Ni-centered one, consistent with experiments. We further predict unprecedented, near-quantitative lower bounds for the η OER , of 0.48 and 0.14 V for pure and Fe-doped β-NiOOH(1211), respectively. Our hybrid density functional theory calculations favor a heretofore unpredicted pathway involving an iron(IV)-oxo species, Fe 4+ =O. We posit that an iron(IV)-oxo intermediate that stably forms under a low-coordination environment and the favorable discharge of Ni 3+ to Ni 2+ are key to β-NiOOH's OER activity.

Original languageEnglish (US)
Pages (from-to)693-705
Number of pages13
JournalJournal of the American Chemical Society
Volume141
Issue number1
DOIs
StatePublished - Jan 9 2019

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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