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U.S. Department of Energy
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Method for the preparation of metal colloids in inverse micelles and product preferred by the method

Patent ·
OSTI ID:868468

A method is provided for preparing catalytic elemental metal colloidal particles (e.g. gold, palladium, silver, rhodium, iridium, nickel, iron, platinum, molybdenum) or colloidal alloy particles (silver/iridium or platinum/gold). A homogeneous inverse micelle solution of a metal salt is first formed in a metal-salt solvent comprised of a surfactant (e.g. a nonionic or cationic surfactant) and an organic solvent. The size and number of inverse micelles is controlled by the proportions of the surfactant and the solvent. Then, the metal salt is reduced (by chemical reduction or by a pulsed or continuous wave UV laser) to colloidal particles of elemental metal. After their formation, the colloidal metal particles can be stabilized by reaction with materials that permanently add surface stabilizing groups to the surface of the colloidal metal particles. The sizes of the colloidal elemental metal particles and their size distribution is determined by the size and number of the inverse micelles. A second salt can be added with further reduction to form the colloidal alloy particles. After the colloidal elemental metal particles are formed, the homogeneous solution distributes to two phases, one phase rich in colloidal elemental metal particles and the other phase rich in surfactant. The colloidal elemental metal particles from one phase can be dried to form a powder useful as a catalyst. Surfactant can be recovered and recycled from the phase rich in surfactant.

Research Organization:
AT & T CORP
DOE Contract Number:
AC04-76DP00789
Assignee:
United States of America as represented by United States (Washington, DC)
Patent Number(s):
US 5147841
OSTI ID:
868468
Country of Publication:
United States
Language:
English

References (4)

Formation of Metal Colloids in Inverse Micelles and Microemulsions journal January 1989
Monodisperse colloidal metal particles from nonaqueous solutions: Catalytic behavior in hydrogenation of but-1-ene of platinum, palladium, and rhodium particles supported on pumice journal January 1987
Photochemical production of hydrogen from water journal May 1985
The preparation of monodisperse colloidal metal particles from microemulsions journal November 1982