X-RAY PHOTOELECTRON SPECTROSCOPY ANALYSIS OF POTASSIUM ADSORPTION ONTO nu -SiO//2: OBSERVATION OF REACTIVE SURFACE DEFECT SITES.

Robert Caracciolo, Steve Garofalini

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Abstract

The adsorption of potassium onto a clean silica surface has been studied by X-ray photoelectron spectroscopy (XPS). The fracture surface of silica was cleaned by Ar** plus sputtering and exposed to potassium metal vapor for 10-s intervals up to 50 s, resulting in 0. 2 to 2 monolayer coverage. High-resolution XPS spectra were recorded for the K 2p, O 1s, and Si 2p photoelectrons at each potassium exposure. Potassium uptake curves were generated from peak areas which suggest the mechanism of adsorption. Curve synthesis techniques were employed on the O 1s spectra to identify the various chemical states present. A decrease in a reactive state is observed as the number of nonbridging oxygen states increases. Angle-resolved XPS was also used to determine the relative position, with respect to depth, of these reactive sites, showing that they are at a higher concentration near the surface.

Original languageEnglish
JournalJournal of the American Ceramic Society
Volume71
Issue number7
Publication statusPublished - Jul 1988

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ASJC Scopus subject areas

  • Ceramics and Composites

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