title: 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.
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.
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.
authors.forename: Narayanappa
authors.initials: N
authors.lastname: Sivasankar
authors.forename: Walter W
authors.initials: WW
authors.lastname: Weare
authors.forename: Heinz
authors.initials: H
authors.lastname: Frei
mesh_terms: D002384:Catalysis; D006861:Hydrogen Peroxide / Q000138:chemical synthesis* / Q000737:chemistry; D007495:Iridium / Q000737:chemistry; D008027:Light; D049329:Nanostructures; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; C044458:iridium oxide; D007495:Iridium; D006861:Hydrogen Peroxide