Synthesis of alloy nanoparticles as a stable core for core-shell electrocatalysts

Patent metadata

Field	Value
Publication number	US-9761884-B2
Application number	US-201414309293-A
Country	US
Kind code	B2
Filing date	Jun 19, 2014
Priority date	Jun 19, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A method for making tungsten-alloy nanoparticles that are useful for fuel cell applications includes a step of combining a solvent system and a surfactant to form a first mixture. A tungsten precursor is introduced into the first mixture to form a tungsten precursor suspension. The tungsten precursor suspension is heated to form tungsten nanoparticles. The tungsten nanoparticles are combined with carbon particles to form carbon-nanoparticle composite particles. The carbon-nanoparticle composite particles are combined with a metal salt to form carbon-nanoparticle composite particles with adhered metal salt, the metal salt including a metal other than tungsten. The third solvent system is then removed. A two-stage heat treatment is applied to the carbon-nanoparticle composite particles with adhered metal salt to form carbon supported tungsten-alloy nanoparticles. A method for making carbon supported tungsten alloys by reducing a tungsten salt and a metal salt is also provided.

First claim

What is claimed is:

1. A method for making tungsten-alloy nanoparticles comprising:
a) combining a first solvent system and a surfactant to form a first mixture;
b) introducing a tungsten precursor into the first mixture to form a tungsten precursor suspension;
c) heating the tungsten precursor suspension to form tungsten nanoparticles;
d) combining the tungsten nanoparticles with carbon particles in an optional second solvent system to form carbon-nanoparticle composite particles;
e) contacting the carbon-nanoparticle composite particles with a metal salt in an optional third solvent system to form carbon-nanoparticle composite particles with adhered metal salt or product particles thereof, the metal salt including a metal other than tungsten;
f) collecting carbon-nanoparticle composite particles with adhered metal salt or product particles thereof; and
g) applying a two stage heat treatment to the carbon-nanoparticle composite particles with adhered metal salt or product particles thereof to form carbon supported tungsten-alloy nanoparticles, the two stage heat treatment including:
heating the carbon-nanoparticle composite particles with adhered metal salt or product particles thereof to a first heat treatment temperature under a first hydrogen-containing environment; and
heating the carbon-nanoparticle composite particles with adhered metal salt or product particles thereof to a second heat treatment temperature under a second hydrogen-containing environment, the second heat treatment temperature being higher than the first heat treatment temperature, the first hydrogen-containing environment including hydrogen in a higher concentration than in the second hydrogen-containing environment.

2. The method of claim 1 wherein the metal salt include a component selected from the group consisting of nickel salts, iron salts, cobalt salts, copper salts, molybdenum salts, iridium salts, palladium salts, and combinations thereof.

3. The method of claim 1 wherein the tungsten-alloy nanoparticles include a metal selected from the group consisting of nickel, iron, cobalt, copper, molybdenum, irridium, palladium, and combinations thereof.

4. The method of claim 1 wherein the tungsten-alloy nanoparticles include a tungsten nickel alloy.

5. The method of claim 1 wherein the tungsten-alloy nanoparticles have an average spatial dimension from about 1 to 10 nanometers.

6. The method of claim 1 wherein the first solvent system includes solvent with a boiling point greater than about 200° C.

7. The method of claim 1 wherein the carbon particles have an average spatial dimension from about 10 to 100 nanometers.

8. The method of claim 1 wherein the first solvent system includes dibenzyl ether.

9. The method of claim 1 wherein the surfactant is selected from the group consisting of cetyltrimethylammonium bromide, oleylamine, oleic acid, and combinations thereof.

10. The method of claim 1 wherein the tungsten precursor suspension is heated to a temperature from about 200° C. to 300° C. to form the carbon-nanoparticle composite particles.

11. The method of claim 1 wherein the first solvent system and the second solvent system each independently include a component selected from the group consisting of ethanol, tetrahydofuran, o-xylene, and combinations thereof.

12. The method of claim 1 wherein the first heat treatment temperature is from about 350° C. to 500° C. and the second heat treatment temperature is from about 500° C. to 800° C.

13. The method of claim 1 wherein the first hydrogen-containing environment includes from 10 to 100 weight percent hydrogen.

14. The method of claim 1 wherein the second hydrogen-containing environment includes less than 15 weight percent hydrogen.

15. The method of claim 1 further comprising coating the carbon supported tungsten-alloy nanoparticles with a 0.1 to 2 nanometer platinum layer.

16. A method for making tungsten-nickel nanoparticles comprising:
a) combining a first solvent system and a surfactant to form a first mixture, the first solvent system including a solvent having a boiling point greater than 200° C.;
b) introducing a W(CO) 6 into the first mixture to form a tungsten precursor suspension;
c) heating the tungsten precursor suspension to form tungsten nanoparticles;
d) combining the tungsten nanoparticles with carbon particles in an optional second solvent system to form carbon-nanoparticle composite particles;
e) contacting the carbon-nanoparticle composite particles with a nickel salt in an optional third solvent system to form carbon-nanoparticle composite particles with adhered nickel salt or product particles thereof;
f) collecting the carbon-nanoparticle composite particles with adhered nickel salt or product particles thereof; and
g) applying a two stage heat treatment to the carbon-nanoparticle composite particles with adhered nickel salt or product particles thereof to form carbon supported tungsten-nickel nanoparticles, the two stage heat treatment including:
heating the carbon-nanoparticle composite particles with adhered nickel salt or product particles thereof to a first heat treatment temperature under a first hydrogen-containing environment; and
heating the carbon-nanoparticle composite particles with adhered nickel salt or product particles thereof to a second heat treatment temperature under a second hydrogen-containing environment, the second heat treatment temperature being higher than the first heat treatment temperature, the first hydrogen-containing environment including hydrogen in a higher concentration than in the second hydrogen-containing environment.

17. The method of claim 16 wherein the tungsten-nickel nanoparticles have an average spatial dimension from about 1 to 10 nanometers.

18. The method of claim 16 wherein the first hydrogen-containing environment includes from 10 to 100 weight percent hydrogen.

19. Carbon supported tungsten-alloy nanoparticles comprising:
carbon particles having an average spatial dimension from about 10 to 100 nanometers; and
tungsten alloy nanoparticles supported on the carbon particles, the tungsten alloy nanoparticles having an average spatial dimension from about 1 to 10 nanometers.

20. The carbon supported tungsten-alloy nanoparticles of claim 19 comprising tungsten and a metal selected from the group consisting of nickel, iron, cobalt, copper, molybdenum, iridium, palladium, and combinations thereof.

21. A method for making tungsten-alloy nanoparticles comprising:
a) combining a first solvent system and a surfactant to form a first mixture;
b) introducing a tungsten precursor into the first mixture to form a tungsten precursor suspension;
c) heating the tungsten precursor suspension to form tungsten nanoparticles;
d) combining the tungsten nanoparticles with a metal salt to form a second mixture;
e) adding carbon particles to the second mixture to form a third mixture;
f) collecting product particles from the third mixture; and
g) applying a two stage heat treatment to the product particles to form carbon supported tungsten-alloy nanoparticles, the two stage heat treatment including:
heating the carbon-nanoparticle composite particles with adhered metal salt to a first heat treatment temperature under a first hydrogen-containing environment; and
heating the carbon-nanoparticle composite particles with adhered metal salt to a second heat treatment temperature under a second hydrogen-containing environment, the second heat treatment temperature being higher than

Assignees

• Gm Global Tech Operations Llc

Inventors

• Atwan Mohammed
• Kongkanand Anusorn
• Carpenter Michael K

Classifications

• B22F1/054

  Nanosized particles · CPC title

• B22F1/16

  Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) · CPC title

• C22C2026/002

  Carbon nanotubes · CPC title

• C22C1/058

  Chemistry & Metallurgy · mapped topic

• H01M4/8657

  layered · CPC title