Electrocatalyst for fuel cells using support body resistant to carbon monoxide poisoning

• US 20040248730A1
• Filed: 06/03/2003
• Published: 12/09/2004
• Est. Priority Date: 06/03/2003
• Status: Active Grant

• Current Assignee: Korea Institute of Energy Research
• Original Assignee: Korea Institute of Energy Research
• Inventors: Lee, Won-Yong, Yang, Tae-Hyun, Park, Gu-Gon, Kim, Chang-Soo, Kim, Young-Gi
• Granted Patent: US 7,432,221 B2
• Time in Patent Office: Days
• US Class Current: 502/185
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 23/40 of the platinum group metals
• CPC Class Codes: B01J 23/56 Platinum group metals
• CPC Class Codes: B01J 23/89 combined with noble metals
• CPC Class Codes: B01J 35/60 characterised by their surface properties or porosity
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 4/925 supported on carriers, e.g. powder carriers
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Disclosed is an electrocatalyst for fuel cells, in which a porous carbon material including pores having a diameter smaller than a kinetic diameter of carbon monoxide is used as a support body and contact probability between an activated metal and carbon monoxide is decreased, thereby preventing fuel cell performance from being degraded by carbon monoxide. The electrocatalyst is obtained by adsorbing 10-80 parts by weight of an activated metal to 20-90 parts by weight of a porous support body, characterized in that the porous support body has a total surface area of 200-2,500 m²/g including an outer surface thereof and an inner surface of pores thereof, and has a plurality of pores penetrating into an interior of the support body with an average diameter of 2-15 nm and a total volume of 0.4-2.0 m³/g, and the activated metal is alloyed with 20-95 at % of platinum and 5-80 at % of one metal selected from among Ru, Sn, Os, Rh, Ir, Pd, V, Cr, Co, Ni, Fe and Mn. As for such an electrocatalyst, carbon monoxide does not fundamentally come in contact with the activated metal adsorbed to the inner surface of the pores of the support body, thereby minimizing degradation of fuel cell performance, thus overcoming fuel-feeding problems.

Claims

1. An electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning, comprising an activated metal adsorbed on a surface of the support body consisting mainly of carbon, wherein the support body has a plurality of pores penetrating into an interior thereof to form a porous support body, the activated metal being adsorbed and reduced onto an outer surface of the porous support body and an inner surface of the pores.

2. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, wherein the pores are 2-15 nm in an average diameter of each pore entrance.

3. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, wherein a total surface area of the porous support body is 200-2,000 m²/g, including the outer surface of the porous support body and the inner surface of the pores penetrating into the interior of the support body.

4. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, herein a total volume of the pores formed in the porous support body is 0.4-2.0 m³/g.

5. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, wherein the pores formed in the porous support body comprise 50-80 vol % of mesopores and 20-50 vol % of micropores.

6. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, wherein the activated metal comprises a Pt-M alloy, in which M is a metal selected from the group consisting of Ru, Sn, Os, Rh, Ir, Pd, V, Cr, Co, Ni, Fe and Mn.

7. The electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning as defined in claim 1, wherein the activated metal is used in an amount of 10-80 parts by weight, based on the total 100 parts by weight of the porous support body and the activated metal.

8. A method of making an electrocatalyst for fuel cells using a support body resistant to carbon monoxide poisoning, comprising:

providing an activated metal;

providing a support body consisting mainly of carbon, wherein the support body has a plurality of pores penetrating into an interior thereof to form a porous support body;

adsorbing the activated metal onto an outer surface of the porous support body and an inner surface of the pores; and

reducing the activated metal on the outer surface of the porous support body and the inner surface of the pores.

9. The method as defined in claim 8, wherein the pores are 2-15 nm in an average diameter of each pore entrance.

10. The method as defined in claim 8, wherein a total surface area of the porous support body is 200-2,500 m²/g, including the outer surface of the porous support body and the inner surface of the pores penetrating into the interior of the support body.

11. The method as defined in claim 8, wherein a total volume of the pores formed in the porous support body is 0.4-2.0 m³/g.

12. The method as defined in claim 8, wherein the pores formed in the porous support body comprise 50-80 vol % of mesopores and 20-50 vol % of micropores.

13. The method as defined in claim 8, wherein the activated metal comprises a Pt-M alloy, in which M is a metal selected from the group consisting of Ru, Sn, Os, Rh, Ir, Pd, V, Cr, Co, Ni, Fe and Mn.

14. The method as defined in claim 8, wherein the activated metal is used in an amount of 10-80 parts by weight, based on the total 100 parts by weight of the porous support body and the activated metal.

15. A method of reducing degradation of an electrocatalyst for fuel cells as a result of carbon monoxide poisoning, comprising:

providing an electrocatalyst having activated metal adsorbed on a surface of a support body consisting mainly of carbon, the support body having a plurality of pores penetrating into an interior thereof to form a porous support body, the pores having a diameter larger than the kinetic diameter of a hydrogen molecule diameter and smaller than the kinetic diameter of a carbon monoxide molecule, the activated metal being adsorbed and reduced onto an outer surface of the porous support body and an inner surface of the pores;

exposing the electrocatalyst to a fuel gas comprising hydrogen and carbon monoxide; and

contacting the hydrogen in the fuel gas with the reduced activated metal adsorbed onto the outer surface of the porous support body and the inner surface of the pores while preventing substantial contact of the carbon dioxide in the fuel gas with the reduced activated metal adsorbed onto the inner surface of the pores.