In situ iridium LIII-edge X-ray absorption and surface enhanced Raman spectroscopy of electrodeposited iridium oxide films in aqueous electrolytes

Yibo Mo, Ionel C. Stefan, Wen Bin Cai, Jian Dong, Paul Carey, Daniel Alberto Scherson

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59 Citations (Scopus)

Abstract

Structural and electronic aspects of IrO2 films prepared by electrodeposition on Au substrates were investigated by in situ LIII-edge X-ray absorption and surface enhanced Raman spectroscopies in both acid and alkaline aqueous solutions. Linear correlations were found between the extent of oxidation of Ir3+ in the films determined from a statistical fit of the white line, which includes contributions from each of the sites differing by a single electron, and from coulometric analysis of the voltammetric curves. Analysis of the extended X-ray absorption fine structure (EXAFS) yielded Ir-O bond lengths decreasing in the sequence 2.02, 1.97, and 1.93 Å for Ir3+, Ir4+, and Ir5+ sites, respectively. Whereas SERS provided evidence for the presence of crystalline IrO2 in the highly hydrated films, the lack of intense shells in the Fourier transform of the EXAFS function beyond the nearest oxygen neighbors indicates that the films do not display long-range order.

Original languageEnglish
Pages (from-to)3681-3686
Number of pages6
JournalJournal of Physical Chemistry B
Volume106
Issue number14
DOIs
Publication statusPublished - 2002 Apr 11
Externally publishedYes

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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