Quantitative Raman spectroscopy of monolayers physisorbed on graphitic carbon surfaces

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:466471

Kagan, M R ^[1]

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1. Ohio State Univ., Columbus, OH (United States)

The wide potential range of graphitic carbon materials has prompted their use as electrodes in a variety of electrochemical applications. Despite this popularity, detailed analysis of the factors controlling the electrochemical performance of graphitic carbon materials has been complicated by their tendency to adsorb organic molecules present in their surrounding environment. The goal of our research has been to explore the utility of Raman spectroscopy as a tool for studying organic molecules adsorbed on various graphitic carbon surfaces. In these studies, the sensitivity of the surface Raman technique needed to be determined. This required that a method for obtaining reproducible surface coverages be developed. This was accomplished using solution phase Langmuir adsorption isotherm theory. The detection limits for our particular experimental arrangement was then determined as a function of adsorbate surface coverage and adsorbate surface Raman scattering cross section. A comparison between surface and solution phase Raman scattering cross sections was performed in order to determine whether or not the easily determined solution phase Raman scattering cross sections could serve as a general predictor of the much more difficult to determine surface Raman scattering cross sections. The ability of graphitic carbon surfaces to quench fluorescence was investigated as a means of extending the utility of Resonance Raman spectroscopy to dye molecules excited near the peak of their absorption maxima. Solution or solid phase Raman spectra of these same molecules could not be obtained due to excessive fluorescence interference. Finally, the effect of microscopic surface area on adsorbate Raman signal intensity was investigated.

• OSTI ID: 466471
• Report Number(s): CONF-951017--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
ADSORPTION
CARBON
ELECTRODES
FLUORESCENCE
ORGANIC COMPOUNDS
RAMAN SPECTRA
SCATTERING
SURFACE AREA
SURFACE PROPERTIES