In situ, time-resolved normal incidence reflectance spectroscopy of polycrystalline platinum microelectrodes in aqueous electrolytes

Iosif Fromondi, Ping Shi, Atsushi Mineshige, Daniel Alberto Scherson

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In situ normal incidence reflectance spectra of polycrystalline Pt microelectrodes have been monitored as a function of the applied potential in aqueous 0.5 M H 2SO 4 using a He-Ne laser source (633 nm) and a beam splitter/microscope objective arrangement. Data recorded during voltammetric cycles in Ar-purged solutions revealed a linear correlation between the normalized change in reflectance, ΔR/R = (R s - R ref)/R ref (where R s and R ref 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 spectra were also collected in CO-saturated 0.5 M H 2SO 4 during chronocoulometric measurements involving judiciously selected limits for both the potential step and duty cycle parameters. Analysis of these results made it possible to extract contributions to the current derived from oxide formation during oxidation of adsorbed and bulk CO, based strictly on the optical response.

Original languageEnglish
Pages (from-to)36-39
Number of pages4
JournalJournal of Physical Chemistry B
Issue number1
Publication statusPublished - 2005 Jan 13
Externally publishedYes


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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