表面層,表面炭素種のRaman-Ellipsometry 分光分析

抄録

A combined system of Raman spectroscopy and ellipsometry is developed for the study of catalyst surfaces on which a chemical reaction is taking place. A surface layer or a surface compound produced in the reaction is analyzed by an ellipsometer and a Raman spectrometer, the products in gas phase by a mass spectrometer, and the surface species by the Raman spectrometer. A special reaction cell is designed for the optical measurement under high temperature-high/normal gas pressure conditions.
The Boudouard and dissociation reactions of CO molecules on Fe and Fe₃O₄ catalysts are studied. A surface layer produced by diffused C and O atoms and a thin oxide layer formed during the CO dissociation reaction are observed, and their thicknesses and the dielectric constants are determined. Raman spectra reveal several kinds of carbon species such as a defective graphite, an Fe carbide and an unstable surface graphite formed on the Fe and Fe₃O₄ surfaces. The reactivity of those species with H₂O is studied.