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Surface Plasmon Resonance Evaluation of Colloidal Metal Aerogel FiltersWe have fabricated aerogels containing gold, silver, and platinum nanoparticles for gas catalysis applications. By applying the concept of an average or effective dielectric constant to the heterogeneous interlayer surrounding each particle, we extend the technique of immersion spectroscopy to porous or heterogeneous media. Specifically, we apply the predominant effective medium theories for the determination of the average fractional composition of each component in this inhomogeneous layer. Hence, the surface area of metal available for catalytic gas reaction is determined. The technique is satisfactory for statistically random metal particle distributions but needs further modification for aggregated or surfactant modified systems. Additionally, the kinetics suggest that collective particle interactions in coagulated clusters are perturbed during silica gelation resulting in a change in the aggregate geometry.
Document ID
19990089685
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Smith, David D.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Sibille, Laurent
(Universities Space Research Association Huntsville, AL United States)
Cronise, Raymond J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Noever, David A.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Subject Category
Inorganic And Physical Chemistry
Distribution Limits
Public
Copyright
Other

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