Strategies in controlling the homogeneity of zirconia-silica aerogels: Effect of preparation on textural and catalytic properties

Journal Article · Mon Aug 01 04:00:00 EDT 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1254· OSTI ID:6618306

Miller, J B; Rankin, S E; Ko, E I ^[1]

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1. Carnegie Mellon Univ., Pittsburgh, PA (United States)

The authors have used a sol-gel synthesis, followed by supercritical drying, to prepare zirconia-silica aerogels with different molecular ratios and varying degrees of homogeneity. Even at levels as low as 1-5 mol%, silica retards surface area loss and phase transformations that would normally occur in zirconia samples upon heat treatment. At 5 mol% silica, prehydrolysis of the silicon precursor tetraethylorthosilicate produces mixed oxide gels whose textural properties, most notably surface area and pore size distribution, vary with gel time in a manner that parallels pure zirconia aerogels. This evidence suggests that prehydrolysis effectively matches precursor reactivities and, in turn, produces homogeneous mixed oxides. Choosing an alternative silicon precursor, tetramethylorthosilicate, or chemically modifying the zirconium precursor by treatment with acetylacetone is also effective in matching precursor reactivity. Well-mixed 95 mol% zirconia-5 mol% silica aerogels are more active in 1-butene isomerization than are poorly mixed samples or either single component aerogel. 46 refs., 14 figs., 2 tabs.

• OSTI ID: 6618306
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 148:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKENES
BUTENES
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COLLOIDS
DISPERSIONS
GELS
HETEROGENEOUS CATALYSIS
HYDROCARBONS
ISOMERIZATION
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SYNTHESIS
TEXTURE
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES