Direct observation of a hydroperoxide surface intermediate upon visible light-driven water oxidation at an Ir oxide nanocluster catalyst by rapid-scan FT-IR spectroscopy

Narayanappa Sivasankar; Walter W Weare; Heinz Frei

doi:10.1021/ja205300a

Direct observation of a hydroperoxide surface intermediate upon visible light-driven water oxidation at an Ir oxide nanocluster catalyst by rapid-scan FT-IR spectroscopy

J Am Chem Soc. 2011 Aug 24;133(33):12976-9. doi: 10.1021/ja205300a. Epub 2011 Aug 1.

Authors

Narayanappa Sivasankar¹, Walter W Weare, Heinz Frei

Affiliation

¹ Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.

PMID: 21770440
DOI: 10.1021/ja205300a

Abstract

A surface hydroperoxide intermediate has been detected upon oxidation of water at an Ir oxide nanocluster catalyst system under pulsed excitation of a [Ru(bpy)(3)](2+) visible light sensitizer by recording of the OO vibrational mode at 830 cm(-1). Rapid-scan FT-IR spectroscopy of colloidal H(2)O, D(2)O, and D(2)(18)O solutions in the attenuated total reflection mode allowed spectral assignment of IrOOH on the basis of an observed D shift of 30 cm(-1), and (18)O shifts of 24 cm(-1) ((16)O(18)O) and 46 cm(-1) ((18)O(18)O). The laser pulse response of the infrared band is consistent with the kinetic relevancy of the intermediate. This is the first observation of a surface intermediate of oxygen evolution at an Ir oxide multielectron catalyst.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Catalysis
Hydrogen Peroxide / chemical synthesis*
Hydrogen Peroxide / chemistry
Iridium / chemistry
Light*
Nanostructures
Oxidation-Reduction
Spectroscopy, Fourier Transform Infrared / methods*
Water / chemistry*

Substances

Water
iridium oxide
Iridium
Hydrogen Peroxide