Polarization modulation infrared reflection - absorption spectioscopy and surface-enhanced Raman spectroscopy are used to interrogate the behavior of the Keggin-type polyoxometalate α-[SiW 12O 20] 4- on Ag and Au electrode surfaces. Assignment of specific vibrational modes and their behavior as a function of potential show that α-[SiW 12O 40] 4- adsorbs strongly on Ag but not on Au. On Ag, analysis of the potential-dependent spectroscopy provides insight into the behavior of this species on the electrode surface, especially at cathodic potentials In particular, the spectroscopy shows that the molecule reorients on the Ag electrode surface at the potential where a voltammetric wave is found in the solution-based voltammetry. This reorientation inhibits the oxidation of the Ag surface-confined species.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry