Method for synthesis of ruthenium nanoparticles with face-centered cubic and hexagonal close-packed structures

Patent metadata

Field	Value
Publication number	US-2016311028-A1
Application number	US-201615201852-A
Country	US
Kind code	A1
Filing date	Jul 5, 2016
Priority date	Jul 9, 2014
Publication date	Oct 27, 2016
Grant date	—

Abstract

The present disclosure provides for methods for preparing ruthenium nanoparticles characterized by face centered cubic crystallographic structure characterized by small particle size, substantially homogeneous particle size distribution, substantially uniform spherical shape, and substantial high temperature stability. The present disclosure further provides for methods for preparing ruthenium nanoparticles characterized by face hexagonal close packed crystallographic structure characterized by small particle size, substantially homogeneous particle size distribution, substantially uniform spherical shape, and substantial high temperature stability.

First claim

What is claimed is:

1 . A method of synthesizing ruthenium nanoparticles, the method comprising:
preparing a precursor solution comprising a ruthenium precursor compound and glycol; heating the precursor solution to a temperature of from about 90° C. to about 225° C.; adding an acid salt compound reducing agent to the precursor solution form a reaction mixture comprising nucleated ruthenium; incubating the reaction mixture in a growth phase at a temperature of from about 150° C. to about 225° C. to form ruthenium nanoparticles in the reaction mixture; and separating ruthenium nanoparticles from the reaction mixture.

2 . The method of claim 1 wherein the ruthenium precursor compound is selected from the group consisting of ruthenium (III) acetylacetonate, RuCl 3 .xH 2 O, and combinations thereof.

3 . The method of claim 1 wherein the acid salt compound is sodium acetate dissolved in a glycol.

4 . The method of claim 1 wherein the acid salt compound is added to the precursor solution at a rate sufficient to achieve an essentially spontaneous quantitative formation of ruthenium nanoparticle nuclei as indicated by an essentially instantaneous change in color of the solution to black.

5 . The method of claim 1 , further comprising a ligand exchange step comprising:
preparing a suspension comprising the ruthenium nanoparticles, an alcohol solvent, oleic acid, and oleylamine; mixing and optionally sonicating the suspension; and separating ruthenium nanoparticles from the suspension.

6 . The method of claim 1 wherein:
the ruthenium concentration in the reaction mixture is from about 1 mmole per liter to about 10 mmoles per liter;
the acid salt concentration in the reaction mixture is from about from about 10 mmole per liter to about 100 mmoles per liter; and
the mole ratio of acid salt compound to ruthenium in the reaction mixture is from about 5:1 to about 20:1.

7 . The method of claim 1 wherein the ruthenium precursor compound is ruthenium(III) acetylacetonate, the glycol is triethylene glycol, the acid salt compound is added to the solution at a temperature of from about from 170° C. to about 225° C., the growth phase temperature is from about 170° C. to about 225° C., and the ruthenium nanoparticles are characterized by face centered cubic (FCC) crystallographic structure having an average diameter of from about 1.3 nm to about 3.3 nm and a particle size distribution such that at least 90% of the particles have a diameter within a range of ±0.5 nm of the average particle size diameter.

8 . The method of claim 1 wherein the ruthenium precursor compound is ruthenium chloride, the glycol is ethylene glycol, the acid salt compound is added to the solution at a temperature of from about 100° C. to about 120° C., the growth phase temperature is from about 125° C. to about 225° C., and the ruthenium nanoparticles are characterized by hexagonal close packed (HCP) crystallographic structure having an average diameter of from about 1.5 nm to about 3.5 nm and a particle size distribution such that at least 90% of the particles have a diameter within a range of ±0.5 nm of the average particle size diameter.

9 . The method of claim 1 wherein a plurality of the ruthenium nanoparticles are characterized by isotropic spherical morphology.

10 . A method of synthesizing ruthenium nanoparticles with face centered cubic (FCC) crystallographic structure, the method comprising:
preparing a precursor solution comprising a ruthenium precursor compound and glycol; heating the precursor solution to a temperature of from about 170° C. to about 225° C.; adding an acid salt compound reducing agent to the precursor solution to form a reaction mixture comprising nucleated ruthenium; incubating the reaction mixture in a growth phase at a temperature of from about 170° C. to about 225° C. to form ruthenium nanoparticles in the reaction mixture, the nanoparticles having FCC crystallographic structure; and separating the ruthenium nanoparticles from the reaction mixture.

11 . The method of claim 10 wherein:
the ruthenium concentration in the reaction mixture is from about 1 mmole per liter to about 10 mmoles per liter;
the acid salt concentration in the reaction mixture is from about from about 10 mmole per liter to about 100 mmoles per liter; and
the mole ratio of acid salt compound to ruthenium in the reaction mixture is from about 5:1 to about 20:1.

12 . The method of claim 10 wherein the ruthenium precursor compound is ruthenium (III) acetylacetonate and wherein the acid salt compound is sodium acetate.

13 . The method of claim 10 wherein the acid salt compound is added to the solution at a rate sufficient to achieve an essentially spontaneous quantitative formation of ruthenium nanoparticles as indicated by an essentially spontaneous change in color of the solution to black.

14 . The method of claim 10 , further comprising a ligand exchange step comprising:
preparing a suspension comprising the ruthenium nanoparticles, an alcohol solvent, oleic acid, and oleylamine; mixing and optionally sonicating the suspension; and separating ruthenium nanoparticle from the suspension.

15 . The method of claim 10 wherein a plurality of the ruthenium nanoparticles are characterized by isotropic spherical morphology, an average diameter of from about 1.5 nm to about 3.5 nm, and by a particle size distribution such that at least 90% of the particles have a diameter within a range of ±0.5 nm of the average particle size diameter.

16 . A method of synthesizing ruthenium nanoparticles with hexagonal close packed (HCP) crystallographic structure, the method comprising:
preparing a precursor solution comprising a ruthenium precursor compound and a glycol; heating the precursor solution to a temperature of from about 50° C. to about 120° C.; adding an acid salt compound reducing agent to the precursor solution to form a reaction mixture comprising nucleated ruthenium; incubating the reaction mixture in a growth phase at a temperature of from about 125° C. to about 225° C. to form ruthenium nanoparticles in the reaction mixture, the nanoparticles having HCP crystallographic structure; and separating the ruthenium nanoparticles from the reaction mixture.

17 . The method of claim 16 wherein:
the ruthenium concentration in the reaction mixture is from about 1 mmole per liter to about 10 mmoles per liter;
the acid salt concentration in the reaction mixture is from about from about 10 mmole per liter to about 100 mmoles per liter; and
the mole ratio of acid salt compound to ruthenium in the reaction mixture is from about 5:1 to about 20:1.

18 . The method of claim 16 wherein the ruthenium precursor compound is RuCl 3 ·xH 2 O.

19 . The method of claim 16 wherein the acid salt compound is sodium acetate dissolved in a glycol.

20 . The method of claim 16 , further comprising a ligand exchange step comprising:
preparing a suspension comprising the ruthenium nanoparticles, an alcohol solvent, oleic acid, and oleylamine; mixing and optionally sonicating the suspension; and separating ruthenium nanoparticles from the suspension.

21 . The method of claim 16 wherein a plurality of the ruthenium nanoparticles are characterized by isotropic spherical morphology, an average diameter of from about 1.5 nm to about 3.5 nm and by a particle size distribution such that at least 90% of the particles have a diameter within a range of ±0.5 nm of the average particle size diame

Assignees

• Honda Motor Co Ltd

Inventors

• Harutyunyan Avetik
• Chou Nam Hawn

Classifications

• B01J23/462 Primary

  Ruthenium · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J37/04

  Mixing {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• C22B61/00

  Obtaining metals not elsewhere provided for in this subclass (iron C21) · CPC title