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Positron annihilation spectroscopy for chemical analysis (PASCA)

Thesis/Dissertation ·
OSTI ID:5699564
Positron Annihilation Spectroscopy (PAS) is a new and novel method to determine surface areas and to study internal surface properties of porous materials. The effect of adsorption of environmentally important gases such as NO/sub 2/, SO/sub 2/, O/sub 2/, and NO on the porous materials has been studied at room temperature. Different chemical states of adsorbed gas molecules on the surface and those trapped in the cages are found. By measuring the Ps chemical reactivities with molecules, those adsorbed on the surfaces and trapped in the microvoids can be analyzed to below ppm levels. The results on the changes in the Ps intensity from the metal-ion adsorbed zeolites can yield information with regard to the internal surface properties such as electric field on the surface of zeolite, surface acidity, and catalytic activity. PAS has been proved as a non-destructive, in-situ surface chemical and analytical technique which can probe the properties of hidden caves and voids in porous solids.
Research Organization:
Missouri Univ., Kansas City (USA)
OSTI ID:
5699564
Country of Publication:
United States
Language:
English