Method of producing stable, active and mass-producible PtNi catalysts through preferential co etching

Patent metadata

Field	Value
Publication number	US-11088371-B2
Application number	US-201916659314-A
Country	US
Kind code	B2
Filing date	Oct 21, 2019
Priority date	Dec 22, 2016
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A method of forming metallic particles, comprising: providing precursor particles comprising a transition metal alloy; supplying carbon monoxide (CO) under reaction conditions which differentially remove a first alloy metal from the precursor particles at a faster rate than a second alloy metal; and, maintaining the reaction conditions until the precursor particles are converted to the particles. The precursor particles may comprise PtNi4, and the particles may be Pt3Ni, formed as hollow nanoframes on a carbon support.

First claim

What is claimed is:

1. A method of forming particles, comprising:
providing Pt—Ni precursor particles having a bulk ratio of Pt to Ni of less than 4:1;
supplying carbon monoxide under reaction conditions which differentially remove Ni from Pt—Ni precursor particles at a faster rate than Pt; and
maintaining the reaction conditions until at least a portion of the particles have at least one portion having an enriched ratio of Pt to Ni of greater than or equal to 4:1.

2. The method according to claim 1 , wherein the Pt—Ni precursor particles comprise PtNi 4 .

3. The method according to claim 1 , wherein the Pt—Ni precursor particles have a bulk ratio of Pt to Ni of at least 3:1.

4. The method according to claim 1 , wherein at least 50 mol % of the nickel is removed from the precursor particles with respect to the particles.

5. The method according to claim 1 , wherein the particles are nanocrystals.

6. The method according to claim 1 , wherein the particles are formed under non-aqueous reaction conditions.

7. The method according to claim 1 , wherein the precursor particles are prepared through a colloidal synthesis process.

8. A Pt—Ni nanoparticle, comprising a segregated Pt thin layer having a Pt to Ni ratio of at least 4:1, strained to Pt—Ni alloy surfaces.

9. The Pt—Ni nanoparticle according to claim 8 , wherein the nanoparticle has a down-shift d-band center.

10. The Pt—Ni nanoparticle according to claim 8 , formed by a process comprising:
providing a precursor particle comprising a platinum-nickel alloy;
supplying carbon monoxide under reaction conditions which differentially remove nickel from the precursor particles at a faster rate than platinum; and
maintaining the reaction conditions until the precursor particle is converted to the Pt—Ni nanoparticle having the segregated Pt thin layer having a Pt to Ni ratio of at least 4:1.

11. The Pt—Ni nanoparticle according to claim 10 , wherein the precursor particle comprises PtNi 4 .

12. The Pt—Ni nanoparticle according to claim 10 , wherein the nanoparticle has a bulk ratio of Pt to Ni of at least 3:1.

13. The Pt—Ni nanoparticle according to claim 10 , wherein at least 50 mol % of the nickel is removed from the precursor particle with respect to the nanoparticle.

14. The Pt—Ni nanoparticle according to claim 10 , wherein the particle is formed under non-aqueous reaction conditions.

15. The Pt—Ni nanoparticle according to claim 10 , wherein the precursor particle is prepared through a colloidal synthesis process.

16. A metallic nanoparticle, formed by a process comprising:
providing a precursor nanoparticle comprising a Pt—Ni metal alloy having a Pt:Ni ratio of less than 4:1;
supplying carbon monoxide under reaction conditions which differentially remove Ni from the Pt—Ni metal alloy of the precursor nanoparticle at a faster rate than Pt; and
maintaining the reaction conditions until the precursor nanoparticle is converted to a nanoparticle comprising a surface layer portion layer having a Pt to Ni ratio of at least 4:1, strained to a Pt—Ni alloy surface having a lower Pt to Ni ratio.

17. The metallic nanoparticle according to claim 16 , wherein the precursor nanoparticle has a carbon core.

18. The metallic nanoparticle according to claim 16 , wherein the nanoparticle is configured to catalyze at least one oxidation-reduction reaction (ORR) chemical reaction.

19. The metallic nanoparticle according to claim 16 , wherein the nanoparticle comprises a segregated platinum thin layer strained to the platinum-nickel alloy surfaces having a down-shift d-band center.

20. The metallic nanoparticle according to claim 16 , wherein at least 50 mol % of the Ni is removed from the precursor nanoparticle with respect to the nanoparticle.

Assignees

• Univ New York State Res Found
• The Research Foundation For The State Univ

Inventors

• Fang Jiye
• Luan Yiliang

Classifications

• C22C19/03

  based on nickel · CPC title

• C22C5/04

  Alloys based on a platinum group metal · CPC title

• H01M4/921 Primary

  Alloys or mixtures with metallic elements · CPC title

• B01J37/0072

  Preparation of particles, e.g. dispersion of droplets in an oil bath · CPC title

• H01M4/926

  on carbon or graphite · CPC title