TY - JOUR
T1 - In situ iridium LIII-edge X-ray absorption and surface enhanced Raman spectroscopy of electrodeposited iridium oxide films in aqueous electrolytes
AU - Mo, Yibo
AU - Stefan, Ionel C.
AU - Cai, Wen Bin
AU - Dong, Jian
AU - Carey, Paul
AU - Scherson, Daniel Alberto
PY - 2002/4/11
Y1 - 2002/4/11
N2 - 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.
AB - 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.
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U2 - 10.1021/jp014452p
DO - 10.1021/jp014452p
M3 - Article
AN - SCOPUS:0037061947
SN - 1089-5647
VL - 106
SP - 3681
EP - 3686
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 14
ER -