Electrochemical activation of Cp∗ iridium complexes for electrode-driven water-oxidation catalysis

Julianne M. Thomsen, Stafford W. Sheehan, Sara M. Hashmi, Jesús Campos, Ulrich Hintermair, Robert H. Crabtree, Gary W Brudvig

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

Organometallic iridium complexes bearing oxidatively stable chelate ligands are precursors for efficient homogeneous water-oxidation catalysts (WOCs), but their activity in oxygen evolution has so far been studied almost exclusively with sacrificial chemical oxidants. In this report, we study the electrochemical activation of Cp∗Ir complexes and demonstrate true electrode-driven water oxidation catalyzed by a homogeneous iridium species in solution. Whereas the Cp∗ precursors exhibit no measurable O2-evolution activity, the molecular species formed after their oxidative activation are highly active homogeneous WOCs, capable of electrode-driven O2evolution with high Faradaic efficiency. We have ruled out the formation of heterogeneous iridium oxides, either as colloids in solution or as deposits on the surface of the electrode, and found indication that the conversion of the precursor to the active molecular species occurs by a similar process whether carried out by chemical or electrochemical methods. This work makes these WOCs more practical for application in photoelectrochemical dyads for light-driven water splitting.

Original languageEnglish
Pages (from-to)13826-13834
Number of pages9
JournalJournal of the American Chemical Society
Volume136
Issue number39
DOIs
Publication statusPublished - Sep 4 2014

ASJC Scopus subject areas

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

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