| Abstract
| - In situ normal incidence reflectance spectra of polycrystalline Pt microelectrodes have been monitored as afunction of the applied potential in aqueous 0.5 M H2SO4 using a He−Ne laser source (633 nm) and a beamsplitter/microscope objective arrangement. Data recorded during voltammetric cycles in Ar-purged solutionsrevealed a linear correlation between the normalized change in reflectance, ΔR/R = (Rs − Rref)/Rref (where Rsand Rref are the light intensities measured by the detector at the sampling, s, and reference potentials, ref,respectively), and the extent of oxidation of the Pt surface over a wide coverage range. Reflectance spectrawere also collected in CO-saturated 0.5 M H2SO4 during chronocoulometric measurements involving judiciouslyselected limits for both the potential step and duty cycle parameters. Analysis of these results made it possibleto extract contributions to the current derived from oxide formation during oxidation of adsorbed and bulkCO, based strictly on the optical response.
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