Reactive oxygen species in iridium-based OER catalysts
Tremendous effort has been devoted towards elucidating the fundamental reasons for the higher activity of hydrated amorphous Ir oxyhydroxides (IrO ) in the oxygen evolution reaction (OER) in comparison with their crystalline counterpart, rutile-type IrO , by focusing on the metal oxidation state. He...
Saved in:
Published in | Chemical science (Cambridge) Vol. 7; no. 11; pp. 6791 - 6795 |
---|---|
Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
01.01.2016
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Tremendous effort has been devoted towards elucidating the fundamental reasons for the higher activity of hydrated amorphous Ir
oxyhydroxides (IrO
) in the oxygen evolution reaction (OER) in comparison with their crystalline counterpart, rutile-type IrO
, by focusing on the metal oxidation state. Here we demonstrate that, through an analogy to photosystem II, the nature of this reactive species is not solely a property of the metal but is intimately tied to the electronic structure of oxygen. We use a combination of synchrotron-based X-ray photoemission and absorption spectroscopies,
calculations, and microcalorimetry to show that holes in the O 2p states in amorphous IrO
give rise to a weakly bound oxygen that is extremely susceptible to nucleophilic attack, reacting stoichiometrically with CO already at room temperature. As such, we expect this species to play the critical role of the electrophilic oxygen involved in O-O bond formation in the electrocatalytic OER on IrO
. We propose that the dynamic nature of the Ir framework in amorphous IrO
imparts the flexibility in Ir oxidation state required for the formation of this active electrophilic oxygen. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2041-6520 2041-6539 |
DOI: | 10.1039/c6sc01860b |