Catalyst carrier and fuel cell using the same

• US 7,919,427 B2
• Filed: 04/28/2010
• Issued: 04/05/2011
• Est. Priority Date: 01/27/2004
• Status: Expired due to Fees

• Current Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Iinou, Satoshi, Ota, Ken-ichiro, Sudoh, Akinori, Ishihara, Akimitsu
• Primary Examiner(s): Hailey; Patricia L
• Application Number:
  US12/769,591
• Publication Number:
  US 20100216057A1
• Time in Patent Office: 342 Days
• Field of Search: 502/180, 502/182, 502/185, 423/447.1, 423/447.2, 977/742, 977/844
• US Class Current: 502/185
• CPC Class Codes: B01J 21/185 Carbon nanotubes carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 23/42 Platinum
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 37/0036 Grinding
• CPC Class Codes: B01J 37/031 Precipitation
• CPC Class Codes: B01J 37/16 Reducing
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/9041 Metals or alloys H01M4/92 takes precedence
• CPC Class Codes: H01M 4/9083 on carbon or graphite
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/844 Growth by vaporization or dissociation of carbon source using a high-energy heat source, e.g. electric arc, laser, plasma, e-beam

Abstract

A catalyst carrier, being characterized in that a catalyst metal for promoting an oxidation-reduction reaction is carried on a vapor-grown carbon fiber having an average outer diameter of from 2 nm to 500 nm, which has been subjected to a crushing treatment so as to have a BET specific surface area of from 4 m²/g to 100 m²/g and an aspect ratio of from 1 to 200, and exhibiting high activity per unit amount of a catalyst metal, a low reaction resistance and an improved output density, and is useful for a fuel cell; a production method thereof and a fuel cell using the catalyst carrier.

Claims

1. A catalyst carrier used for a fuel cell comprising a catalyst metal for promoting an oxidation-reduction reaction carried on a vapor-grown carbon fiber having a multi-layer graphene sheet structure, said vapor-grown carbon fiber comprising, at an end portion thereof, a discontinuous surface of a graphene sheet having a fracture surface and a closed portion having a continuous surface connecting an end portion of a graphene sheet with an end portion of an adjacent graphene sheet;

and a hollow space in a center axis of the vapor-grown carbon fiber.

2. The catalyst carrier as claimed in claim 1, wherein the discontinuous surface is configured in the direction of the circumference of the vapor-grown carbon fiber.

3. The catalyst carrier as claimed in claim 1, wherein the discontinuous surface and the continuous surface are present at a same end of the vapor-grown carbon fiber.

4. The catalyst carrier as claimed in claim 1, wherein the discontinuous surface and the continuous surface are present at different ends of the vapor-grown carbon fiber.

5. The catalyst carrier as claimed in claim 1 having four or more graphene sheets, wherein outer two graphene sheets layers of the vapor-grown carbon fiber form a continuous surface over an entire outer circumference of an end portion of the vapor-grown fiber and inner two graphene sheets form both a discontinuous surface and a continuous surface at different inner circumferential positions of an end portion of the vapor-grown carbon fiber.

6. The catalyst carrier as claimed in claim 1, wherein outer two graphene sheets of the vapor-grown carbon fiber form a continuous surface over an entire outer circumference of an end portion of the vapor-grown fiber and all other graphene sheets form a discontinuous surface at an end portion of the vapor-grown fiber.

7. The catalyst carrier as claimed in claim 1, wherein an outermost graphene sheet and a graphene sheet fourth from the outermost layer and second and third graphene sheets from the outermost layer are combined with each other, respectively, to form a continuous surface over an entire outer circumference of an end portion of the vapor-grown fiber and all other graphene sheets form a discontinuous surface at an end portion of the vapor-grown fiber.

8. The catalyst carrier as claimed in claim 1, wherein an outermost graphene sheet and a graphene sheet sixth from the outermost layer and second and fifth graphene sheets from the outermost layer are combined with each other, respectively, to form a continuous surface over an entire outer circumference of an end portion of the vapor-grown fiber and all other graphene sheets form a discontinuous surface at an end portion of the vapor-grown fiber.

9. The catalyst carrier as claimed in claim 1, wherein the vapor-grown carbon fiber is entirely closed at one end thereof and has both a continuous surface and a discontinuous surface at the other end thereof.

10. The catalyst carrier as claimed in claim 1, wherein the vapor-grown carbon fiber has each of a continuous surface and a discontinuous surface at both ends thereof.

11. The catalyst carrier as claimed in claim 1, wherein the vapor-grown carbon fiber has an average outer diameter of from 15 nm to 500 nm, a BET specific surface area of from 4 m²/g to 100 m²/g and an aspect ratio of from 1 to 200.