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The Measurement of Extinction Coefficients Using a New Infrared Micropulse Reactor Technique: Adsorption of CO on Silica-supported Pt

Volume 36, Number 3 (June 1982) Page 320-322

Sárkány, János; Gonzalez, Richard D.


The increased sophistication in infrared instrumentation, coupled with recent advances in the limits of detection of commercially available gas chromatographs, has resulted in the revival of infrared spectroscopy as a useful tool in the study and characterization of supported-metal catalysts. In its initial applications, infrared spectroscopy was used as a tool in the surface characterization of supported-metal catalysts. The general procedure was to use a diatomic molecule, whose adsorptive behavior was well understood, as a surface probe to obtain information regarding the disposition of the underlying surface-metal atoms. In its more recent applications, it has become possible to observe the structure of adsorbed molecules under reaction conditions. For cases in which an infrared cell coupled to a gas chromatograph is used as a single-pass differential reactor, it is possible to measure reaction rates and to study the structure of the species adsorbed on the surface simultaneously. In studying the kinetics of surface reactions, it would be useful to have some knowledge of surface coverages under reaction conditions. This will ultimately enable investigators to test assumed mechanisms derived from experimentally determined rates by obtaining independent measurements of surface coverages. In order to do this quantitatively, it is necessary to measure extinction coefficients for both adsorbed reactants and products at process temperatures and pressures.