Method of producing stable, active and mass-producible Pt3Ni catalysts through preferential co etching

• US 10,454,114 B2
• Filed: 12/21/2017
• Issued: 10/22/2019
• Est. Priority Date: 12/22/2016
• Status: Active Grant

• Current Assignee: The Research Foundation for The State University of New York (State University of New York)
• Original Assignee: The Research Foundation for The State University of New York (State University of New York)
• Inventors: Fang, Jiye, Luan, Yiliang
• Primary Examiner(s): Hailey, Patricia L.
• Application Number:
  US15/851,232
• Publication Number:
  US 20180316023A1
• Time in Patent Office: 670 Days
• Field of Search: 502185, 502326, 502337, 502339, 420456, 420466
• CPC Class Codes: B01J 23/892 Nickel and noble metals
• CPC Class Codes: B01J 37/0072 Preparation of particles, e.g. dispersion of droplets in an oil bath
• CPC Class Codes: C22C 19/03 based on nickel
• CPC Class Codes: C22C 5/04 Alloys based on a platinum group metal
• CPC Class Codes: H01M 4/8657 layered
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: Y02E 60/50 Fuel cells

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.

Claims

1. A method of forming particles, comprising:

providing precursor particles comprising size and crystallographic facet controlled tetrahexahedral (THH) nanocrystals (NCs) of a transition metal alloy prepared through a colloidal synthesis process;

supplying carbon monoxide under reaction conditions which differentially remove a first alloy metal component from the precursor particles at a faster rate than a second alloy metal component; and

maintaining the reaction conditions until the precursor particles are converted to the particles, having a skin of the second alloy metal component, and a bulk composition comprising the first alloy metal component and the second alloy metal component.

2. The method according to claim 1, wherein the transition metal alloy comprises a platinum-nickel alloy.

3. The method according to claim 2, wherein the transition metal alloy of the precursor particles has a molar predominance of nickel over platinum.

4. The method according to claim 2, wherein the transition metal alloy of the precursor particles comprises PtNi₄.

5. The method according to claim 4, wherein the bulk composition of the particles comprises Pt₃Ni and the skin comprises Pt.

6. The method according to claim 2, wherein at least mol 50% of the nickel is removed from the precursor particles with respect to the particles.

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

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

9. The method according to claim 1, wherein the particles are catalytic nanoparticles having a specific activity of at least 2.5 mA cm⁻

1 at 0.90 V vs. a reversible hydrogen electrode (RHE).

10. The method according to claim 1, wherein the precursor particles comprise PtNi₄ transition metal alloy tetrahexahedral nanoparticles, prepared using a colloidal reaction mixture containing NiCl₂.6H₂O, oleylamine and 1-octadecene, loaded on a carbon black support, and the particles comprise Pt₃Ni.

11. The method according to claim 1, further comprising using the particles as a catalyst for at least one of:

an oxidation-reduction reaction;

an alcohol oxidation reaction;

a CO/NO oxidation reaction;

a formic acid oxidation reaction;

a hydrogen evolution reaction (HER) in water splitting;

an hydrogenolysis reaction;

an isomerization reaction;

a dehydrogenolysis reaction; and

an aromatization reaction.

12. The method according to claim 1, wherein the precursor particles comprise iron.

13. A catalytic particle, comprising a segregated Pt thin layer strained to a surface of a hollow Pt—

Ni alloy tetrahexadral nanoframe having a molar excess of platinum, and having a specific activity of at least 2.5 mA cm<sup>−

1</sup> at 0.90 V vs. a reversible hydrogen electrode (RHE).

14. The catalytic particle according to claim 13, wherein the Pt—

Ni tetrahexahedral nanoframe is hollow, has a down-shift d-band center, and is a size and crystallographic facet controlled tetrahexahedral (THH) nanocrystal (NCs) prepared through a colloidal synthesis process.

15. The catalytic particle according to claim 13, wherein the Pt—

Ni tetrahexahedral nanoframe is 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 tetrahexahedral nanoframe.

16. The catalytic particle according to claim 14, wherein the Pt—

Ni tetrahexahedral nanoframe comprises a hollow, stable and catalytically active Pt₃Ni nanoframe, which is supported on a carbon support.

17. A metallic nanoparticle, formed by a process comprising:

providing a precursor nanoparticle comprising a transition metal alloy;

supplying carbon monoxide under reaction conditions which differentially remove a first transition metal from the transition metal alloy of the precursor nanoparticle at a faster rate than a second metal; and

maintaining the reaction conditions until the precursor nanoparticle is converted to a hollow nanostructure,

wherein the transition metal alloy comprises a platinum-nickel alloy; and

the hollow nanostructure comprises a platinum-nickel alloy tetrahexahedral nanoframe, comprising a segregated platinum thin layer strained to the platinum-nickel alloy surfaces having a down-shift d-band center.

18. The metallic nanoparticle according to claim 17, wherein the hollow nanostructure comprises a tetrahexahedral hollow nanoframe formed of an alloy having a molar excess of platinum.

19. The metallic nanoparticle according to claim 17, wherein the hollow nanostructure is provided on a support structure configured to catalyze at least one chemical reaction selected from the group consisting of:

an oxidation-reduction reaction (ORR);

an alcohol oxidation reaction;

a formic acid oxidation reaction;

a CO/NO oxidation reaction;

an hydrogen evolution reaction (HER) in water splitting;

an hydrogenolysis reaction;

an isomerization reaction;

a dehydrogenolysis reaction; and

an aromatization reaction.

20. The metallic nanoparticle according to claim 17, wherein the platinum-nickel alloy tetrahexahedral nanoframe has a specific activity of at least 2.5 mA cm⁻

1 at 0.90 V vs. a reversible hydrogen electrode (RHE).