Synthesis of oxide-coated metal clusters
- Purdue Univ., West Lafayette, IN (United States). School of Engineering
Fish-eye particles consisting of metal clusters (Ag, Cu) a few nanometers in diameter encapsulated within a thin layer ({minus}1 nm) of silica are produced using aerosol synthesis procedures. The authors present a method for predicting stable fish-eye nanostructures and describe synthesis techniques for producing significant quantities of silica-encapsulated metal nanoparticles. For many metal/oxide pairs, gas phase formation of oxide encapsulated metal particles is thermodynamically favorable. Using known surface free energies and binary phase diagrams, it is possible to predict whether SiO{sub 2}-encapsulated metal clusters will form in the gas phase. Two conditions which must be satisfied are: (1) that the surface free energy of the metal is higher than that of Si; and (2) that the metal composition in the particle is greater than the eutectic composition in the metal/Si phase diagram. Ag-SiO{sub 2} and Cu-SiO{sub 2} are two examples of systems which readily form fish-eye structures. Two types of gas phase cluster sources are used at Purdue for producing encapsulated metal nanoparticles. The Multiple Expansion Cluster Source (MECS) is a well established apparatus which produces small quantities ({minus}50 mg/hr) of very uniform materials using resistive heating for evaporation. The new Arc Cluster Evaporation Source (ACES) offers much higher production rates (> 1 g/hr) using DC arc evaporation. These two cluster sources make possible the study of a unique class of materials.
- OSTI ID:
- 522327
- Report Number(s):
- CONF-961202-; ISBN 1-55899-361-4; TRN: IM9739%%48
- Resource Relation:
- Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of Nanophase and nanocomposite materials 2; Komarneni, S. [ed.] [Pennsylvania State Univ., University Park, PA (United States)]; Parker, J.C. [ed.] [Nanophase Technologies Corp., Burr Ridge, IL (United States)]; Wollenberger, H.J. [ed.] [Hahn-Meitner Inst., Berlin (Germany)]; PB: 573 p.; Materials Research Society symposium proceedings, Volume 457
- Country of Publication:
- United States
- Language:
- English
Similar Records
DOE Hydrogen Sorption Center of Excellence: Synthesis and Processing of Single-Walled Carbon Nanohorns for Hydrogen Storage and Catalyst Supports
State selective dynamics of molecules, clusters, and nanostructures