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Pretreatment of CO oxidation catalystsCO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.
Document ID
19890005559
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Vannorman, John D.
(Old Dominion Univ. Norfolk, VA, United States)
Date Acquired
September 5, 2013
Publication Date
September 1, 1988
Publication Information
Publication: Hampton Inst., NASA/American Society for Engineering Educat
Subject Category
Inorganic And Physical Chemistry
Accession Number
89N14930
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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