CARBON-SUPPORTED CoSe2 NANOPARTICLES FOR OXYGEN REDUCTION AND HYDROGEN EVOLUTION IN ACIDIC ENVIRONMENTS

• US 20100233070A1
• Filed: 02/18/2010
• Published: 09/16/2010
• Est. Priority Date: 02/19/2009
• Status: Abandoned Application

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company), Universite de Poitiers
• Original Assignee: Universite de Poitiers
• Inventors: Feng, Yongjun, He, Ting, Alonso-Vante, Nicolas
• Application Number:
  US12/708,162
• Publication Number:
  US 20100233070A1
• Time in Patent Office: Days
• US Class Current: 423/579
• CPC Class Codes: H01M 4/8842 Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor
• CPC Class Codes: H01M 4/8878 Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
• CPC Class Codes: H01M 4/90 Selection of catalytic material
• CPC Class Codes: H01M 4/9083 on carbon or graphite
• CPC Class Codes: Y02E 60/32 Hydrogen storage
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The present teachings are directed to preparation of carbon-supported CoSe₂ nanoparticles via an in situ surfactant free method, and use of the same for oxygen reduction and hydrogen evolution reactions. The CoSe₂ nanoparticles have two kinds of structure after heat treatment at different temperatures: orthorhombic at 300° C. and cubic at 400° C. The latter structure has higher oxygen reduction activity and hydrogen evolution activity than the former in 0.5 M H₂SO₄. Electron transfers of about 3.5- and about 3.7-electrons were observed for 20 wt. % CoSe₂/C nanoparticles, after heat treatment at 300° C. and 400° C., per oxygen molecule during the oxygen reduction process, respectively.

Claims

1. A method of preparing carbon-supported CoSe₂ nanoparticles comprising:

providing a support material;

providing a Co precursor;

providing a Se precursor;

contacting the support material and the Co precursor in a non-aqueous surfactant free reaction mixture;

heating the reaction mixture to a maximum temperature of no greater than about 200°

C.;

contacting the Se precursor with the reaction mixture;

heating the reaction mixture to a maximum temperature of no greater than about 200°

C., and

isolating a supported CoSe₂-containing component.

2. The method according to claim 1, further comprising heating the supported CoSe₂-containing component to about 300°

C. to produce a supported orthorhombic phase CoSe₂-containing component.

3. The method according to claim 1, further comprising heating the supported CoSe₂-containing component to about 400°

C. to produce a supported cubic phase CoSe₂-containing component.

4. The method according to claim 1, wherein the support material comprises carbon.

5. The method according to claim 1, wherein each heating step comprises heating for less than about 1 hour.

6. The method according to claim 1, wherein each heating step comprises heating for less than about 30 minutes.

7. The method according to claim 1, wherein each heating step comprises heating to a maximum temperature of no greater than about 150°

C.

8. A method of reducing oxygen comprising

providing oxygen,

providing a Co and Se-containing electrocatalyst component,

contacting oxygen with the Co and Se-containing electrocatalyst component, and

transferring from 3 to 4 electrons per oxygen molecule from the electrocatalyst to the oxygen to thereby reduce the oxygen.

9. The method according to claim 8, wherein the Co and Se-containing electrocatalyst component comprises CoSe₂ nanoparticles.

10. The method according to claim 9, wherein the CoSe₂ nanoparticles in either an orthorhombic or cubic structure.

11. The method according to claim 9, wherein the CoSe₂ nanoparticles are in a cubic structure.

12. The method according to claim 8, wherein the transfer of electrons occurs in an acidic medium.

13. The method according to claim 12, wherein the acidic medium comprises 0.5 M H₂SO₄.

14. The method according to claim 8, wherein the Co and Se-containing electrocatalyst component comprises a supported Co and Se-containing electrocatalyst component.

15. The method according to claim 14, wherein the supported Co and Se-containing electrocatalyst component comprises a carbon supported Co and Se-containing electrocatalyst component.

16. The method according to claim 8, wherein the transferring of electrons comprises transferring about 3.5 electrons per oxygen molecule.

17. The method according to claim 8, wherein the transferring of electrons comprises transferring about 3.7 electrons per oxygen molecule.

18. An electrocatalyst for molecular oxygen reduction or hydrogen evolution comprising

a carbon-supported CoSe₂ nanoparticle electrocatalyst,

wherein the carbon-supported CoSe₂ nanoparticles comprise CoSe₂ nanoparticles in an orthorhombic or cubic phase structure.

19. The electrocatalyst according to claim 18, wherein the molecular oxygen reduction comprises

a four-electron transfer at the cathode of the polymer electrolyte fuel cell.

20. A method of evolving hydrogen comprising

providing a hydrogen source,

providing a Co and Se-containing electrocatalyst component,

contacting the hydrogen source with the Co and Se-containing electrocatalyst component, and

transferring electrons from the electrocatalyst to the hydrogen source to evolve hydrogen.

21. The method according to claim 20, wherein the Co and Se-containing electrocatalyst component comprises CoSe₂ nanoparticles.

22. The method according to claim 21, wherein the CoSe₂ nanoparticles are in a cubic structure.

23. The method according to claim 20, wherein the evolution of hydrogen occurs in an acidic medium.

24. The method according to claim 20, wherein the Co and Se-containing electrocatalyst component comprises a supported Co and Se-containing electrocatalyst component.

25. The method according to claim 24, wherein the supported Co and Se-containing electrocatalyst component comprises a carbon supported Co and Se-containing electrocatalyst component.