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 language | English |
|---|---|
| Pages (from-to) | 13826-13834 |
| Number of pages | 9 |
| Journal | Journal of the American Chemical Society |
| Volume | 136 |
| Issue number | 39 |
| DOIs | |
| Publication status | Published - Sep 4 2014 |
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ASJC Scopus subject areas
- Chemistry(all)
- Catalysis
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Electrochemical activation of Cp∗ iridium complexes for electrode-driven water-oxidation catalysis. / Thomsen, Julianne M.; Sheehan, Stafford W.; Hashmi, Sara M.; Campos, Jesús; Hintermair, Ulrich; Crabtree, Robert H.; Brudvig, Gary W.
In: Journal of the American Chemical Society, Vol. 136, No. 39, 04.09.2014, p. 13826-13834.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Electrochemical activation of Cp∗ iridium complexes for electrode-driven water-oxidation catalysis
AU - Thomsen, Julianne M.
AU - Sheehan, Stafford W.
AU - Hashmi, Sara M.
AU - Campos, Jesús
AU - Hintermair, Ulrich
AU - Crabtree, Robert H.
AU - Brudvig, Gary W
PY - 2014/9/4
Y1 - 2014/9/4
N2 - 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.
AB - 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.
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U2 - 10.1021/ja5068299
DO - 10.1021/ja5068299
M3 - Article
VL - 136
SP - 13826
EP - 13834
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 39
ER -