Carbon-based material, electrode catalyst, electrode, gas diffusion electrode, electrochemical device, fuel battery, and process for producing carbon-based material

Patent metadata

Field	Value
Publication number	US-9929411-B2
Application number	US-201314401219-A
Country	US
Kind code	B2
Filing date	Jul 4, 2013
Priority date	Jul 6, 2012
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

A carbon-based material according to the present invention contains dopant atoms of metal and non-metal such as nitrogen. In a radial distribution function obtained by Fourier transform of a K-edge EXAFS of the metal, a ratio of “A” to “B” is equal to or more than 4.0, wherein “A” denotes an intensity of the highest one of peaks around a distance equal to a coordinate bond length between atoms of the metal and the non-metal and “B” denotes an intensity of the highest one of peaks around a distance equal to a metallic bond length between atoms of the metal. Note that when the metal is platinum, in a radial distribution function obtained by Fourier transform of an LIII-edge EXAFS of the platinum, a ratio of “A” to “B” is equal to or more than 4.0.

First claim

The invention claimed is:

1. A carbon-based material prepared by doping a base made of graphite or amorphous carbon particles with atoms of metal and non-metal, the non-metal including at least one of nitrogen, boron, sulfur, and phosphorus,
when the metal is not platinum, in a radial distribution function obtained by Fourier transform of a K-edge extended X-ray absorption fine structure (EXAFS) of the metal, a ratio of “A” to “B” being equal to or more than 4.0, wherein “A” denotes an intensity of a highest one of peaks around a distance equal to a coordinate bond length between atoms of the metal and the non-metal and “B” denotes an intensity of a highest one of peaks around a distance equal to a metallic bond length between atoms of the metal, and
when the metal is platinum, in a radial distribution function obtained by Fourier transform of an LIII-edge extended X-ray absorption fine structure (EXAFS) of the platinum, a ratio of “A” to “B” being equal to or more than 4.0, wherein “A” denotes an intensity of a highest one of peaks around a distance equal to a coordinate bond length between atoms of the platinum and the non-metal and “B” denotes an intensity of a highest one of peaks around a distance equal to a metallic bond length between atoms of the platinum.

2. The carbon-based material as set forth in claim 1 , wherein
a molar ratio of atoms of the metal to atoms of carbon determined by XPS is less than 0.01, and
a molar ratio of atoms of the non-metal to atoms of the carbon is less than 0.05.

3. The carbon-based material as set forth in claim 1 , comprising a core layer and a doped layer covering the core layer,
the core layer substantially consisting of the graphite or the amorphous carbon alone, and
the doped layer containing atoms of the non-metal and the metal.

4. The carbon-based material as set forth in claim 1 , wherein
an X-ray diffraction pattern of the carbon-based material shows that a proportion of an intensity of a highest one of peaks derived from an inactive metal compound and a metal crystal to an intensity of a (002) peak is not more than 0.1.

5. The carbon-based material as set forth in claim 1 , wherein
the carbon-based material has a particle shape.

6. The carbon-based material as set forth in claim 1 , wherein:
the non-metal includes nitrogen; and
the metal includes iron.

7. The carbon-based material as set forth in claim 1 , wherein:
the non-metal includes nitrogen; and
the metal includes at least one of cobalt and manganese.

8. An electrode catalyst comprising the carbon-based material as set forth in claim 1 .

9. An electrode comprising the electrode catalyst as set forth in claim 8 .

10. A gas diffusion electrode comprising the electrode catalyst as set forth in claim 8 .

11. An electrochemical device comprising the electrode as set forth in claim 9 .

12. A fuel battery comprising the electrode as set forth in claim 9 .

13. A process for producing the carbon-based material,
the carbon-based material prepared by doping a base made of graphite or amorphous carbon particles with atoms of metal and non-metal, the non-metal including at least one of nitrogen, boron, sulfur, and phosphorus,
when the metal is not platinum, in a radial distribution function obtained by Fourier transform of a K-edge extended X-ray absorption fine structure (EXAFS) of the metal, a ratio of “A” to “B” being equal to or more than 4.0, wherein “A” denotes an intensity of a highest one of peaks around a distance equal to a coordinate bond length between atoms of the metal and the non-metal and “B” denotes an intensity of a highest one of peaks around a distance equal to a metallic bond length between atoms of the metal, and
when the metal is platinum, in a radial distribution function obtained by Fourier transform of an LIII-edge extended X-ray absorption fine structure (EXAFS) of the platinum, a ratio of “A” to “B” being equal to or more than 4.0, wherein “A” denotes an intensity of a highest one of peaks around a distance equal to a coordinate bond length between atoms of the platinum and the non-metal and “B” denotes an intensity of a highest one of peaks around a distance equal to a metallic bond length between atoms of the platinum,
the process comprising steps of:
preparing a mixture of a non-metal containing compound, a metal compound, and a carbon source material, the non-metal containing compound containing non-metal including at least one of nitrogen, boron, sulfur, and phosphorus, and the carbon source material being selected from a group consisting of graphite and amorphous carbon particles; and
heating the mixture to a temperature ranging from 800° C. to 1000° C. for a time of 45 sec or more but less than 600 sec when the carbon source material is graphite; or
heating the mixture at a temperature ranging from 800° C. to 1000° C. for a time of 30 sec or more but less than 300 sec when the carbon source material is the amorphous carbon particles.

14. The process for producing a carbon-based material as set forth in claim 13 , wherein
the non-metal containing compound has a molecular weight of 800 or less.

15. The process for producing a carbon-based material as set forth in claim 13 , wherein
the non-metal containing compound includes at least one compound selected from a group consisting of pentaethylenehexamine, tetraethylenepentamine, triethylenetetramine, and ethylenediamine.

16. An electrochemical device comprising the gas diffusion electrode as set forth in claim 10 .

17. A fuel battery comprising the gas diffusion electrode as set forth in claim 10 .

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kamai Ryo
• Nakanishi Shuji
• Suzuki Yuya
• Kitade Yuuki
• Hayashi Takao

Classifications

• H01M4/926

  on carbon or graphite · CPC title

• H01M4/8605

  Porous electrodes · CPC title

• H01M4/96

  Carbon-based electrodes · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01G11/32

  Carbon-based · CPC title