Catalytic activity of nanophase metals prepared sonochemically

Journal Article · Sun Dec 31 04:00:00 EST 1995 · Preprints of Papers, American Chemical Society, Division of Fuel Chemistry

OSTI ID:420496

Hyeon, Taeghwan; Fang, Mingming; Cichowlas, A A; Suslick, K S ^[1]

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1. Univ. of Illinois, Urbana, IL (United States); and others

The chemical effects of high intensity ultrasound arise from acoustic cavitation: the formation growth, and implosive collapse of bubbles in a liquid, which generates a transient, localized host spot (1, 2). The local conditions reached have temperatures of {approximately}5000 K, pressures of {approximately}1800 atm, but with cooling rates that exceed 10{sup 10} K/s (3, 4). We have made use of these extreme conditions to develop a new technique for the synthesis of nanostructured heterogeneous catalysts. When irradiated with high intensity ultrasound in low volatility solvents under argon, volatile organometallic precursors produce high surface area solids that consist of agglomerates of nanometer clusters. These nanostructured solids are active heterogeneous catalysts for hydrocarbon reforming and CO hydrogenation. For Fe and Co, nanostructured alloys can be formed of any composition. Using polymeric ligands or oxide supports, the initially formed nanoscale clusters can be trapped as colloids or supported catalysts, respectively. A central focus of recent work in materials chemistry has been the preparation of nanostructured materials (5, 6). A variety of chemical and physical preparative methods have been applied to produce materials with nanometer structure; these include metal evaporation (7), decomposition of organometallic compounds (8), and the reduction of metal salts (9, 10). Sonochemical decomposition of transition metal carbonyl compounds has also been proven to be a useful technique to generate nanophase transition metals (11, 12). One of the advantages of our sonochemical synthesis of nanostructured materials is what various forms of nanophase materials can be generated simply by changing the reaction medium. When precursors are sonicated in high boiling alkane such as decane or hexadecane, nanostructured powders are formed.

• OSTI ID: 420496
• Report Number(s): CONF-950402--
• Journal Information: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Journal Name: Preprints of Papers, American Chemical Society, Division of Fuel Chemistry Journal Issue: 2 Vol. 40; ISSN ACFPAI; ISSN 0569-3772
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
36 MATERIALS SCIENCE
CATALYSTS
CATALYTIC EFFECTS
COBALT ALLOYS
COBALT COMPOUNDS
CYCLOALKANES
DECOMPOSITION
DEHYDROGENATION
FISCHER-TROPSCH SYNTHESIS
IRON ALLOYS
IRON COMPOUNDS
SILICA
SURFACE AREA
SYNTHESIS