Control of nanostructure and activity by alloying and/or segregation

Patent metadata

Field	Value
Publication number	US-11679377-B2
Application number	US-202117161138-A
Country	US
Kind code	B2
Filing date	Jan 28, 2021
Priority date	Jan 28, 2020
Publication date	Jun 20, 2023
Grant date	Jun 20, 2023

Abstract

A method for synthesis of PtNi smooth surface core/shell particles or Nano cages and porous nanocages from segregated nanoparticles.

First claim

We claim:

1. A method of synthesizing Pt shell PtNi core particle comprising the steps of:
forming a reaction mixture comprising a nickel precursor, a reducing agent, and a surfactant comprising oleic acid, a platinum precursor, and a polar solvent;
reacting the reaction mixture at between 200° C. and 300° C. for at least 10 minutes, forming a PtNi nanocage solution;
isolating PtNi nanocages from the PtNi nanoparticle solution;
exposing the PtNi nanocages to oxygen;
forming nickel oxide by reaction of nickel of the PtNi nanocages with the oxygen;
exposing the nickel oxide PtNi nanocages to hydrogen and argon at a temperature of at least 400° C.; and
removing the nickel oxide from at least a portion of the PtNi nanocages.

2. The method of claim 1 , wherein isolation of the PtNi nanocages comprises:
sonicating the PtNi nanocages solution with substrate in chloroform solution;
adding hexane to the sonicated chloroform solution;
precipitating PtNi nanocages; and
collecting the PtNi nanocages by filtration.

3. The method of claim 1 , wherein exposing the PtNi nanocages to oxygen comprises exposure at a temperature of 150° C. to 400° C.

4. The method of claim 3 , wherein exposing the PtNi nanocages to oxygen comprises exposure at a temperature of 150° C. to 300° C.

5. The method of claim 3 , wherein exposing the PtNi nanocages is for 5-20 hours.

6. The method of claim 1 , wherein removing the nickel oxide is by acid leeching.

7. The method of claim 6 , wherein exposing to hydrogen and argon is concurrent with the removal of the nickel oxide by acid leeching.

8. The method of claim 6 , wherein the acid leaching is by exposure of an equal volume of acid to nanoparticle.

9. The method of claim 6 , wherein exposing the nickel oxide PtNi nanocages to hydrogen and argon is at a temperature between 400° C. and 600° C. for 1-4 hours.

10. A method of synthesizing Pt shell PtNi core nanoparticle comprising the steps of:
forming a reaction mixture comprising a nickel precursor, a reducing agent, and a surfactant comprising oleic acid, a platinum precursor, and a polar solvent;
reacting the reaction mixture at between 205° C. and 255° C. for at least 10 minutes forming a PtNi nanoparticle solution;
isolating PtNi nanoparticles from the PtNI nanoparticle solution;
exposing the PtNi nanoparticles to hydrogen and argon at a temperature of at least 400° C.;
exposing the PtNi nanoparticles to oxygen at a temperature of 150° C. to 400° C. for 5-20 hours;
forming nickel oxide on a surface of the PtNi nanoparticles by reaction of nickel of the PtNi nanoparticles with the oxygen; and
removing the nickel oxide from at a portion of the PtNi nanoparticles.

11. The method of claim 10 , wherein isolation of the PtNi nanoparticles comprises:
sonicating the PtNi nanoparticle solution with substrate in chloroform solution;
adding hexane to the sonicated chloroform solution;
precipitating PtNi nanoparticles; and
collecting the PtNi nanoparticles by filtration.

12. The method of claim 10 , wherein exposing the PtNi nanoparticles comprises exposure at a temperature of 150° C. to 300° C.

13. The method of claim 10 , wherein removing the nickel oxide is by acid leeching.

14. The method of claim 13 , wherein the acid leaching is by exposure of an equal volume of acid to nanoparticle.

15. The method of claim 13 , wherein the acid leaching is by exposure to HClO 4 .

16. The method of claim 6 , wherein exposing the nickel oxide PtNi nanoparticles to hydrogen and argon is at a temperature between 400° C. and 600° C. for 1-4 hours.

17. A method of synthesizing Pt shell PtNi core particle comprising the steps of:
forming a reaction mixture comprising a nickel precursor, a reducing agent, and a surfactant comprising oleic acid, a platinum precursor, and a polar solvent;
reacting the reaction mixture at between 200° C. and 300° C. for at least 10 minutes forming a PtNi particle solution comprising PtNi nanoparticles or PtNi nanocages;
isolating PtNi particles from the PtNI particle solution;
exposing the PtNi particles to oxygen;
forming nickel oxide by reaction of nickel of the PtNi particles with the oxygen; and
exposing the PtNi particles to hydrogen and argon at a temperature of at least 400° C.

18. The method of claim 17 , wherein the PtNi particles are nanocages and wherein the exposure to the hydrogen and argon is after the exposure to oxygen.

19. The method of claim 17 , wherein the PtNi particles are nanoparticles and wherein the exposure to the hydrogen and argon is before the exposure to oxygen.

20. The method of claim 17 , wherein exposing the PtNi particles to hydrogen and argon is at a temperature between 400° C. and 600° C. for 1-4 hours.

Assignees

• Uchicago Argonne Llc

Inventors

• Wang Rongyue
• Pupek Krzysztof
• Stamenkovic Vojislav

Classifications

• B22F1/0553

  Complex form nanoparticles, e.g. prism, pyramid, octahedron · CPC title

• B01J35/026

  Operations & Transport · mapped topic

• B22F2301/25

  Noble metals, i.e. Ag Au, Ir, Os, Pd, Pt, Rh, Ru · CPC title

• B22F1/054

  Nanosized particles · CPC title

• B22F9/04

  starting from solid material, e.g. by crushing, grinding or milling ({C22C1/1084 takes precedence}; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C) · CPC title