Photocatalytic Deposition of Metals and Compositions Comprising the Same

• US 20080241640A1
• Filed: 03/26/2008
• Published: 10/02/2008
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: SID Richardson Carbon & Energy Co., Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Rajeshwar, Krishnan, Lin, Wen-Yuan, Carlson, Thomas F., Tacconi, Norma, Wampler, Wesley, Chenthamarakshan, C.R.
• Granted Patent: US 8,143,185 B2
• Time in Patent Office: Days
• US Class Current: 429/40
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 4/9008 Organic or organo-metallic compounds
• CPC Class Codes: H01M 4/9016 Oxides, hydroxides or oxygenated metallic salts
• CPC Class Codes: H01M 4/9075 Catalytic material supported on carriers, e.g. powder carriers H01M4/8807, H01M4/881, H01M4/8814, H01M4/925 take precedence
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 4/923 Compounds thereof with non-metallic elements
• CPC Class Codes: H01M 4/925 supported on carriers, e.g. powder carriers
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A photocatalytic metal deposition process and a resulting nanocomposite are described. The nanocomposite includes an electrically conducting carbonaceous material, a photoactive metal oxide and a metal. Metals for deposition include noble metals, metal alloys and other transition metals in which the metal is laid down precisely and in a predetermined fashion on one or more surfaces of a composite. Deposition provides a high performance electrocatalyst for a number of suitable applications.

Claims

1. An electrocatalyst comprising a nanocomposite that includes an electrically conducting carbonaceous material, a photoactive metal oxide and a metal.

2. The electrocatalyst of claim 1, wherein the electrically conducting carbonaceous material includes a carbon source selected from the group consisting of carbon black, carbon paper, carbon cloth and carbon nanotubes.

3. The electrocatalyst of claim 1, wherein the metal is selected from the group consisting of a transition metal and a metal alloy.

4. The electrocatalyst of claim 1, wherein the metal is platinum.

5. The electrocatalyst of claim 1, wherein the photoactive metal oxide is a semiconductor metal oxide.

6. The electrocatalyst of claim 1, wherein the photoactive metal oxide is titanium dioxide.

7. The electrocatalyst of claim 1, wherein the metal is on a composite surface formed by the electrically conducting carbonaceous material and the photoactive metal oxide.

8. The electrocatalyst of claim 1, herein the electrically conducting carbonaceous material and the photoactive metal oxide form a first composite.

9. The electrocatalyst of claim 1, wherein the metal is in the form of nanoparticles.

10. The electrocatalyst of claim 9, wherein the metal oxide content is less than 40% by mass.

11. The electrocatalyst of claim 1, wherein the metal content is less than 60% by mass.

20. The electrocatalyst of claim 1, wherein the metal is deposited on a composite surface formed by the electrically conducting carbonaceous material and the photoactive metal oxide.

12. A method for preparing an electrocatalyst comprising the step of:

preparing a nanocomposite, wherein the nanocomposite includes an electrically conducting carbonaceous material, a photoactive metal oxide and a metal.

13. The method of claim 12 further comprising depositing the metal on a composite comprising the electrically conducting carbonaceous material and the photoactive metal oxide.

14. The method of claim 13, wherein deposition is photocatalytic

15. The method of claim 12, wherein the metal is selected from the group consisting of a transition metal and a metal alloy.

16. The method of claim 12 further comprising mixing the electrically conducting carbonaceous material and the photoactive metal oxide to form a solution.

17. The method of claim 12, wherein the electrically conducting carbonaceous material and the photoactive metal oxide are prepared as an ink.

18. The method of claim 12 further comprising providing the nanocomposite on a solid support.

19. The method of claim 12, wherein the electrically conducting carbonaceous material includes a carbon source selected from the group consisting of carbon black, carbon paper, carbon cloth and carbon nanotubes.

21. An electrocatalyst for a fuel cell having a membrane electrode assembly, the electrocatalyst comprising a nanocomposite that includes an electrically conducting carbonaceous material, a photoactive metal oxide and a metal.

22. The electrocatalyst of claim 21, wherein the electrically conducting carbonaceous material includes a carbon source selected from the group consisting of carbon black, carbon paper, carbon cloth and carbon nanotubes.

23. The electrocatalyst of claim 21, wherein the photoactive metal oxide is a semiconductor metal oxide.

24. The electrocatalyst of claim 21, wherein the electrically conducting carbonaceous material includes a carbon source selected from the group consisting of carbon black, carbon paper, carbon cloth and carbon nanotubes.

25. The electrocatalyst of claim 21, wherein the electrocatalyst is provided with an anode or cathode of the membrane electrode assembly