Surfactant removal from palladium nanoparticles

Patent metadata

Field	Value
Publication number	US-9553318-B2
Application number	US-201114122546-A
Country	US
Kind code	B2
Filing date	Jun 8, 2011
Priority date	Jun 8, 2011
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A method for removing a surfactant from a palladium nanoparticle includes exposing the palladium nanoparticle to hydrogen and removing the surfactant from the palladium nanoparticle. A method includes synthesizing a palladium nanoparticle using a surfactant. The surfactant influences a geometric property of the palladium nanoparticle and bonds to the palladium nanoparticle. The method also includes exposing the palladium nanoparticle to hydrogen to remove the surfactant from the palladium nanoparticle.

First claim

The invention claimed is:

1. A method for removing a surfactant from a palladium nanoparticle, the method comprising:
exposing the palladium nanoparticle to hydrogen, the exposing including:
applying an electric potential to the palladium nanoparticle, wherein the electric potential applied to the palladium nanoparticle is at or below a potential required for hydrogen adsorption/absorption and hydrogen evolution;
maintaining the electric potential for a time sufficient for hydrogen to penetrate into the palladium nanoparticle; and

removing the surfactant from the palladium nanoparticle.

2. The method of claim 1 , wherein the palladium nanoparticle comprises a chemical substance selected from the group consisting of palladium, palladium alloys and combinations thereof.

3. The method of claim 2 , wherein exposing the palladium nanoparticle to hydrogen comprises:
placing the palladium nanoparticle in a vessel; and
adding hydrogen gas to the vessel so that hydrogen is absorbed by the palladium nanoparticle.

4. The method of claim 1 , wherein the electric potential applied to the palladium nanoparticle measures from about −0.2V to about 0.1V.

5. The method of claim 4 , wherein the electric potential applied to the palladium nanoparticle measures about −0.05V.

6. The method of claim 1 , wherein the electric potential is applied to the palladium nanoparticle for less than about five minutes.

7. The method of claim 6 , wherein the electric potential is applied to the palladium nanoparticle for no more than about one minute.

8. The method of claim 1 , wherein the electric potential is applied to the palladium nanoparticle while the palladium nanoparticle is at a temperature between about 15° C. and about 30° C.

9. The method of claim 1 , wherein the electric potential is applied to the palladium nanoparticle in the presence of a dilute acid.

10. The method of claim 1 , further comprising:
washing the palladium nanoparticle with water after applying the electric potential to the palladium nanoparticle.

11. The method of claim 1 , further comprising:
filtering the palladium nanoparticle after applying the electric potential to the palladium nanoparticle.

12. A method comprising:
synthesizing a palladium nanoparticle using a surfactant, wherein the surfactant influences a geometric property of the palladium nanoparticle and bonds to the palladium nanoparticle; and
exposing the palladium nanoparticle to hydrogen to remove the surfactant from the palladium nanoparticle, the exposing including:
applying an electric potential to the palladium nanoparticle wherein the electric potential applied to the palladium nanoparticle is at or below a potential required for hydrogen adsorption/absorption and hydrogen evolution; and
maintaining the electric potential for a time sufficient for hydrogen to penetrate into the palladium nanoparticle to weaken a bond between the surfactant and the palladium nanoparticle.

13. The method of claim 12 , wherein the palladium nanoparticle comprises a chemical substance selected from the group consisting of palladium, palladium alloys and combinations thereof.

14. The method of claim 13 , wherein the exposing the palladium nanoparticle to hydrogen comprises:
placing the palladium nanoparticle in a vessel; and
adding hydrogen gas to the vessel so that hydrogen is absorbed by the palladium nanoparticle.

15. The method of claim 12 , wherein the electric potential applied to the palladium nanoparticle measures from about −0.2V to about 0.1V.

16. The method of claim 15 , wherein the electric potential applied to the palladium nanoparticle measures about −0.05V.

17. The method of claim 12 , wherein the electric potential is applied to the palladium nanoparticle for less than about five minutes.

18. The method of claim 17 , wherein the electric potential is applied to the palladium nanoparticle for no more than about one minute.

19. A method for removing a surfactant from a palladium nanoparticle, the method comprising:
exposing the palladium nanoparticle to hydrogen at room temperature; and
removing the surfactant from the palladium nanoparticle.

20. A method for removing a surfactant from a palladium nanoparticle, the method comprising:
exposing the palladium nanoparticle to hydrogen at a temperature which remains below 300° C., the exposing including:
applying an electric potential to the palladium nanoparticle wherein the electric potential applied to the palladium nanoparticle is at or below a potential required for hydrogen adsorption/absorption and hydrogen evolution; and
maintaining the electric potential for a time sufficient for hydrogen to penetrate into the palladium nanoparticle to weaken a bond between the surfactant and the palladium nanoparticle; and

removing the surfactant from the palladium nanoparticle.

21. A method comprising:
synthesizing a palladium nanoparticle using a surfactant, wherein the surfactant influences a geometric property of the palladium nanoparticle and bonds to the palladium nanoparticle; and
exposing the palladium nanoparticle to hydrogen at room temperature, the exposing removing the surfactant from the palladium nanoparticle.

22. A method comprising:
synthesizing a palladium nanoparticle using a surfactant, wherein the surfactant influences a geometric property of the palladium nanoparticle and bonds to the palladium nanoparticle; and
exposing the palladium nanoparticle to hydrogen at a temperature which remains below 300° C., the exposing removing the surfactant from the palladium nanoparticle, the exposing including:
applying an electric potential to the palladium nanoparticle wherein the electric potential applied to the palladium nanoparticle is at or below a potential required for hydrogen adsorption/absorption and hydrogen evolution; and
maintaining the electric potential for a time sufficient for hydrogen to penetrate into the palladium nanoparticle to weaken a bond between the surfactant and the palladium nanoparticle.

Assignees

• Shao Minhua
• Audi Ag

Inventors

• Shao Minhua

Classifications

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B22F1/145

  Chemical treatment, e.g. passivation or decarburisation · CPC title

• B22F1/054

  Nanosized particles · CPC title

• B82B3/00

  Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title