Low platinum fuel cell catalysts and method for preparing the same

• US 7,351,444 B2
• Filed: 04/12/2004
• Issued: 04/01/2008
• Est. Priority Date: 09/08/2003
• Status: Expired due to Fees

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Dong, Yi, Li, Yi-Qun, Wang, Ning
• Primary Examiner(s): Cantelmo; Gregg
• Application Number:
  US10/823,088
• Publication Number:
  US 20050053826A1
• Time in Patent Office: 1,450 Days
• Field of Search: 427/115, 502/101, 429/44
• US Class Current: 427/115
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• 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: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

This invention provides novel fuel cell catalysts comprising new series of catalytically active thin-film metal alloys with low platinum concentration supported on nanostructured materials (nanoparticles). In certain embodiments, an integrated gas-diffusion/electrode/catalyst layer can be prepared by processing catalyst thin films and nanoparticales into gas-diffusion media such as Toray or SGL carbon fiber papers. The catalysts can be placed in contact with an electrolyte membrane for PEM fuel cell applications.

Claims

1. A method of preparing a fuel cell element, said method comprising:

providing a plurality of fibers and/or a porous electrode material;

depositing a nanoparticle catalyst on said plurality of fibers and/or porous electrode material;

forming nanoparticles on said plurality of fibers and/or porous electrode material using said nanoparticles catalyst;

forming a catalytically active layer comprising a substantially continuous thin film on said nanoparticles thereby forming a fuel cell element comprising a plurality of fibers bearing nanoparticles partially or fully coated with a catalytically active thin film;

wherein said thin film comprises an alloy having the formula;

Pt_xV_yCo_zNi_w

wherein;

x is greater than 0.06 and less than 1;

y, z, and w are independently greater than zero and less than 1; and

x+y+z+w=1.

2. The method of claim 1, wherein said plurality of fibers comprises a plurality of carbon fibers.

3. The method of claim 2, wherein said plurality of carbon fibers comprise a porous electrode.

4. The method of claim 2 wherein said plurality of fibers comprise a carbon fiber paper.

5. The method of claim 1, wherein said nanoparticle catalyst is a carbon nanotube catalyst and said nanoparticles are carbon nanotubes.

6. The method of claim 5, wherein said nanoparticles are formed by chemical vapor deposition (CVD) or said depositing a nanoparticle catalyst comprises depositing said catalyst on said fibers by chemical vapor deposition (CVD).

7. The method of claim 5, wherein said nanotubes have a length less than 50 μ

m and a width less than 100 nm.

8. The method of claim 5, wherein said nanotubes have a diameter of 50 nm to 100 nm.

9. The method of claim 1, wherein said thin film partially covers the nanoparticles.

10. The method of claim 1, wherein the nanoparticles are fully coated with said thin film.

11. The method of claim 1, wherein said thin film ranges in thickness from 1 to 1000 angstroms.

12. The method of claim 10, wherein said thin film ranges in thickness from 5 to 500 angstroms.

13. The method of claim 10, wherein said thin film ranges in thickness from 5 to 100 angstroms.

14. The method of claim 1, wherein platinum comprises from 6% up to 50% (mole ratio or atomic percentage) of said alloy.

15. The method of claim 14, wherein platinum comprises up to 12% (mole ratio or atomic percentage) of said alloy.

16. The method of claim 13, wherein said alloy contains platinum, vanadium, nickel, and copper.

17. The method of claim 1, wherein x is 0.12.

18. The method of claim 1, wherein x is 0.12, y is 0.07, z is 0.56, and w is 0.25.

19. The method of claim 1, wherein:

said providing a plurality of fibers and/or a porous electrode material comprises providing a carbon fiber paper;

said depositing a nanoparticle catalyst comprises depositing said catalyst by chemical vapor deposition;

said forming nanoparticles comprises forming carbon nanotubes; and

said forming a catalytically active layer comprising depositing a substantially continuous thin film comprising platinum or a platinum alloy.