Metal nanoparticles formed around a nucleus and scalable processes for producing same

Patent metadata

Field	Value
Publication number	US-9700940-B2
Application number	US-201314028487-A
Country	US
Kind code	B2
Filing date	Sep 16, 2013
Priority date	Sep 27, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

Metal nanoparticles and compositions derived therefrom can be used in a number of different applications. Methods for making metal nanoparticles can include providing a first metal salt in a solvent; converting the first metal salt into an insoluble compound that constitutes a plurality of nanoparticle seeds; and after forming the plurality of nanoparticle seeds, reacting a reducing agent with at least a portion of a second metal salt in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles. Each metal nanoparticle can include a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell can include a metal from the second metal salt. The methods can be readily scaled to produce bulk quantities of metal nanoparticles.

First claim

What is claimed is the following:

1. A method comprising:
providing a first metal salt and a second metal salt in a solvent;
converting the first metal salt into an insoluble compound by reducing the first metal salt with a first portion of the second metal salt, the insoluble compound comprising a plurality of nanoparticle seeds; and
after forming the plurality of nanoparticle seeds, reacting a reducing agent with remaining second metal salt or an oxidation product thereof in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles, each metal nanoparticle comprising a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell comprising a metal from the second metal salt.

2. The method of claim 1 , wherein the first metal salt and the second metal salt are different.

3. The method of claim 1 , wherein at least the first metal salt comprises a copper (II) salt.

4. The method of claim 1 , wherein the first metal salt is present in an amount ranging between about 0.05 and about 0.25 stoichiometric equivalents relative to the second metal salt.

5. The method of claim 1 , wherein the reducing agent converts the nanoparticle seeds to a zero-valent metal.

6. The method of claim 1 , wherein the second metal salt comprises a mixture of two or more metal salts and the plurality of metal nanoparticles produced therefrom comprises alloy nanoparticles.

7. The method of claim 1 , wherein the plurality of metal nanoparticles is formed in the presence of a solvent having a content of water that is about 200 ppm or lower.

8. A method comprising:
providing a first metal salt in a solvent, the first metal salt comprising a copper (II) salt;
reducing the first metal salt with a first portion of a second metal salt to form an insoluble copper (I) compound, the insoluble copper (I) compound comprising a plurality of nanoparticle seeds; and
after forming the plurality of nanoparticle seeds, reacting a reducing agent with remaining second metal salt or an oxidation product thereof in the presence of at least one surfactant and the plurality of nanoparticle seeds to form a plurality of metal nanoparticles, each metal nanoparticle comprising a metal shell formed around a nucleus derived from a nanoparticle seed, and the metal shell comprising a metal from the second metal salt.

9. The method of claim 8 , wherein the first metal salt is present in an amount ranging between about 0.05 and about 0.25 stoichiometric equivalents relative to the second metal salt.

10. The method of claim 8 , wherein the reducing agent converts the nanoparticle seeds to a zero-valent metal.

11. The method of claim 8 , wherein the plurality of metal nanoparticles is formed in the presence of a solvent having a content of water that is about 200 ppm or lower.

12. A method comprising:
providing a copper (II) salt in a solvent;
forming an insoluble copper (I) salt having a particle size of about 10 nm or less by reducing the copper (II) salt;
after forming the insoluble copper (I) salt, adding at least one surfactant and a reducing agent thereto; and
reacting the reducing agent with the insoluble copper (I) salt in the presence of the at least one surfactant to form a plurality of copper nanoparticles.

Assignees

• Lockheed Corp

Inventors

• Zinn Alfred A

Classifications

• B22F9/18

  with reduction of metal compounds · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• B01J13/02

  Making microcapsules or microballoons {(for medical preparations A61K9/50)} · CPC title

• B22F1/17

  Metallic particles coated with metal · CPC title

• B22F1/054

  Nanosized particles · CPC title