Metal nanoparticle-decorated nanotubes for gas sensing

Patent metadata

Field	Value
Publication number	US-11585771-B2
Application number	US-202217677716-A
Country	US
Kind code	B2
Filing date	Feb 22, 2022
Priority date	Apr 28, 2017
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

Disclosed herein are methods of producing metal nanoparticle-decorated carbon nanotubes. The methods include forming a reaction mixture by combining a first solution with a second solution, wherein the first solution comprises polymer-coated metal nanoparticles comprising metallic nanoparticles coated with a polymer, and wherein the second solution comprises carbon nanotubes. The methods also include heating the reaction mixture to a temperature greater than a glass transition temperature of the polymer for a time sufficient to cause the polymer-coated metal nanoparticles to bind to the carbon nanotubes forming the metal nanoparticle-decorated carbon nanotubes.

First claim

What is claimed is:

1. A method of producing metal nanoparticle-decorated carbon nanotubes, the method comprising:
forming a reaction mixture by combining a first solution with a second solution, wherein the first solution comprises polymer-coated metal nanoparticles comprising metallic nanoparticles coated with a polymer, and wherein the second solution comprises carbon nanotubes; and
heating the reaction mixture to a temperature greater than a glass transition temperature of the polymer for a time sufficient to cause the polymer-coated metal nanoparticles to bind to the carbon nanotubes forming the metal nanoparticle-decorated carbon nanotubes.

2. The method of claim 1 , wherein the polymer-coated metal nanoparticles are fully-formed prior to forming the reaction mixture.

3. The method of claim 2 , wherein the polymer-coated metal nanoparticles are non-covalently bound to the carbon nanotubes.

4. The method of claim 1 , wherein an average degree of functionalization of the carbon nanotubes with carboxylic acid groups and/or hydroxyl groups is less than 3 wt % based on a total weight of the carbon nanotubes.

5. The method of claim 1 , further comprising:
dispersing the metal nanoparticle-decorated carbon nanotubes in a non-aqueous solvent-based ink.

6. The method of claim 1 , wherein the polymer-coated-metal nanoparticles are coated with a hydrophobic polymer layer.

7. The method of claim 1 , wherein the carbon nanotubes are substantially free of carboxylic acid functional groups and hydroxyl functional groups.

8. A method of producing metal nanoparticle-decorated carbon nanotubes, the method comprising:
forming polymer-coated metal nanoparticles by dispersing a polymer and a salt precursor of a metal into a solvent, reducing the metal salt precursor of the metal with a reducing reagent;
forming a reaction mixture by combining a first solution with a second solution, wherein the first solution comprises polymer-coated metal nanoparticles comprising metallic nanoparticles coated with a polymer, and wherein the second solution comprises carbon nanotubes; and
heating the reaction mixture to a temperature greater than a glass transition temperature of the polymer for a time sufficient to cause the polymer-coated metal nanoparticles to bind to the carbon nanotubes forming the metal nanoparticle-decorated carbon nanotubes.

9. The method of claim 8 , wherein an average degree of functionalization of the carbon nanotubes with carboxylic acid groups and/or hydroxyl groups is less than 3 wt % based on a total weight of the carbon nanotubes.

10. The method of claim 8 , wherein the solvent is both a solvent and a reducing reagent.

11. The method of claim 9 , wherein the solvent and a reducing reagent is ethylene glycol.

12. The method of claim 8 , further involving heating of the solution of polymer and a salt precursor of a metal into the solvent.

13. The method of claim 8 , further involving removal of excess of un-bound polymer onto the polymer-coated nanoparticles by washing with a first solvent, separation and redispersion of the polymer-coated nanoparticles into a second solvent to form a polymer-coated nanoparticle dispersion that is free of unbound polymer, (i.e., does not contain unbound polymer).

14. The method of claim 8 , wherein the carbon nanotubes are selected from a group of single wall and multi-wall carbon nanotubes.

15. The method of claim 8 , wherein the diameter of the metallic core of the polymer coated metal nanoparticles decorated carbon nanotubes is comprised in a range from 1 nm to 20 nm.

16. The method of claim 8 , wherein the diameter of the metallic core of the polymer coated metal nanoparticles decorated carbon nanotubes is comprised in a range from 1 nm to 20 nm and the carbon nanotubes are single wall carbon nanotubes.

17. A method of producing metal alloy nanoparticle-decorated carbon nanotubes, the method comprising:
forming polymer-coated metal nanoparticles by dispersing a polymer and a mixture of two or more salt precursors of metals into a solvent, reducing the mixture of metal salt precursors with a reducing reagent forming polymer coated alloy metal nanoparticles containing two or more metals;
forming a reaction mixture by combining a first solution with a second solution, wherein the first solution comprises polymer-coated metal nanoparticles comprising metallic nanoparticles coated with a polymer, and wherein the second solution comprises carbon nanotubes; and
heating the reaction mixture to a temperature greater than a glass transition temperature of the polymer for a time sufficient to cause the polymer-coated metal nanoparticles to bind to the carbon nanotubes forming the metal nanoparticle-decorated carbon nanotubes.

18. The method of claim 17 , wherein the salt precursors of the polymer-coated metal alloy nanoparticles is selected from a group of metal ions that after reduction process form metals selected from a group of palladium, iridium, rhodium, platinum, and gold.

19. The method of claim 17 , wherein an average degree of functionalization of the carbon nanotubes with carboxylic acid groups and/or hydroxyl groups is less than 3 wt % based on a total weight of the carbon nanotubes.

Assignees

• Palo Alto Res Ct Inc

Inventors

• Iftime Gabriel
• Smith Clinton
• Schwartz David Eric
• Zhang Yong
• Vedharathinam Vedasri

Classifications

• B82Y15/00

  Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors · CPC title

• G01N27/127

  comprising nanoparticles · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• B01J20/3204

  Inorganic carriers, supports or substrates · CPC title

• G01N27/126

  comprising organic polymers · CPC title