Low platinum fuel cell catalysts and method for preparing the same

• US 20050112450A1
• Filed: 07/23/2004
• Published: 05/26/2005
• Est. Priority Date: 09/08/2003
• Status: Abandoned Application

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Dong, Yi, Li, Yi-Qun, Wang, Ning
• Application Number:
  US10/898,669
• Publication Number:
  US 20050112450A1
• Time in Patent Office: Days
• US Class Current: 428/408
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 2008/1095 Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 4/8657 layered
• CPC Class Codes: H01M 4/8825 Methods for deposition of the catalytic active composition
• 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
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

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 composition comprising a plurality of conductive fibers bearing nanoparticles.

2. The composition of claim 1, wherein said conductive fibers are carbon fibers.

3. The composition of claim 1, wherein said nanoparticles are selected from the group consisting of nanotubes, nanofibers, nanohorns, nanopowders, nanospheres, and quantum dots.

4. The composition of claim 1, wherein said nanoparticles are carbon nanotubes.

5. The composition of claim 1, wherein said plurality of conductive fibers comprise a porous electrode.

6. The composition of claim 2, wherein said carbon fibers comprise a porous electrode.

7. The composition of claim 2, wherein said plurality of carbon fibers comprise a carbon paper, or a carbon cloth, or a carbon-impregnated polymer.

8. The composition of claim 1, wherein said plurality of conductive fibers comprise a porous metal sheet.

9. The composition of claim 4, wherein said carbon nanotubes are seeded with one or more catalysts comprising one or more materials selected from the group consisting of Co, Ni, V, Cr, Pt, Ru, Mo, W, Ta, and Zr.

10. The composition of claim 4, wherein said carbon nanotubes are seeded with one or more catalysts selected from the group consisting of Fe_xNi_yCo_1-x-y where 0≦

x≦

1 and 0≦

y≦

1, Co_1-xMo_x where 0≦

x≦

0.3, Co_1-x-yNi_xMo_y where 0.1≦

x≦

0.7 and 0≦

y≦

0.3, Co_1-x-y-zNi_xV_yCr_z where 0≦

x≦

0.7 and 0≦

y≦

0.2, 0≦

z≦

0.2, Ni_1-x-yMo_xAl_y where 0≦

x≦

0.2 and 0≦

y≦

0.2, and Co_1-x-yNi_xAl_y where 0≦

x≦

0.7 and 0≦

y≦

0.2.

11. The composition of claim 4, wherein said carbon nanotubes are seeded with one or more catalysts selected from the group consisting of CO_8.8Mo_1.2, CO_2.2Ni_5.6Mo_2.2, CO_5.7Ni_2.1, V_1.1Cr_1.1, Ni_8.0Mo_1.0Al_1.0, and CO_6.4Ni_2.4Al_1.2.

12. The composition of claim 4, wherein said nanoparticles are nanotubes having a length less than 50 μ

m and a diameter less than about 100 nm.

13. The composition of claim 4, wherein said nanoparticles are nanotubes having a diameter in the range from about 1 nm to about 100 nm.

14. The composition of claim 1, wherein said nanoparticles are coated with a substantially continuous thin film comprising a platinum alloy.

15. The composition of claim 14, wherein said thin film partially covers the nanoparticles.

16. The composition of claim 14, wherein the nanoparticles are fully coated with said thin film.

17. The composition of claim 14, wherein said thin film ranges in thickness from about 1 to about 1000 angstroms.

18. The composition of claim 17, wherein said thin film ranges in thickness from about 5 to about 500 angstroms.

19. The composition of claim 1, wherein said nanoparticles are coated with a non-continuous thin film comprising a platinum alloy.

20. The composition of claim 19, wherein said thin film comprises islands ranging in thickness from about 5 to about 100 angstroms and ranging in area from about 1 to 10⁴nm².

21. The composition of claim 17, wherein said thin film ranges in thickness from about 5 to about 100 angstroms.

22. The composition of claim 21, wherein said thin film comprises an alloy comprising platinum (Pt), vanadium (V), and one or more metals selected from the group consisting of Co, Ni, Mo, Ta, W, and Zr.

23. The composition of claim 22, wherein said thin film comprises an alloy comprising platinum (Pt), vanadium (V), and one or more metals selected from the group consisting of Co, and Ni.

24. The composition of claim 22, wherein platinum comprises up to about 50% (mole ratio or atomic percentage) of said alloy.

25. The composition of claim 22, wherein platinum comprises up to about 12% (mole ratio or atomic percentage) of said alloy.

26. The composition of claim 22, wherein said alloy contains platinum, vanadium, nickel, and cobalt.

27. The composition of claim 22, 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;

x+y+z+w=1.

28. The composition of claim 27, wherein x is 0.12.

29. The composition of claim 27, wherein x is 0.12, y is 0.07, z is 0.56, and w is 0.25.

30-126. -126. (canceled)