SYSTEMS INCLUDING NANOTUBULAR ARRAYS FOR CONVERTING CARBON DIOXIDE TO AN ORGANIC COMPOUND

• US 20100258446A1
• Filed: 04/05/2010
• Published: 10/14/2010
• Est. Priority Date: 04/03/2009
• Status: Abandoned Application

• Current Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Original Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Inventors: Mohapatra, Susanta, Misra, Manoranjan
• Application Number:
  US12/754,269
• Publication Number:
  US 20100258446A1
• Time in Patent Office: Days
• US Class Current: 205/340
• CPC Class Codes: C25B 1/55 Photoelectrolysis

Abstract

A system including nanostructure arrays for converting carbon dioxide to an organic compound, e.g., methanol, which does so, for example, without any external electric energy. In one embodiment, the system for converting carbon dioxide to an organic compound includes an array of nanotubes, which include nanoparticles of an electron mediator, e.g. palladium, dispersed on a surface of the nanotubes, and an electrically conductive fluid. The array of nanotubes is at least partially immersed in the electrically conductive fluid. The system further includes a light source that irradiates the array of nanotubes, a source of carbon dioxide, and an inlet for delivering the carbon dioxide to the electrically conductive fluid whereat at least a portion of the carbon dioxide is converted to a different organic compound, such as methanol, via contact with an irradiated array of nanotubes. In one example, the array is an ordered array of titania nanotubes.

Claims

1. A system for converting carbon dioxide to an organic compound, the system comprising:

an array of nanotubes including nanoparticles of an electron mediator dispersed on a surface of the nanotubes;

an electrically conductive fluid, the array of nanotubes being at least partially immersed in the electrically conductive fluid;

a light source that irradiates the array of nanotubes;

a source of carbon dioxide; and

an inlet for delivering the carbon dioxide to the electrically conductive fluid whereat at least a portion of the carbon dioxide is converted to a different organic compound via contact with an irradiated array of nanotubes.

2. The system of claim 1 wherein the nanotubes are titania nanotubes.

3. The system of claim 2 wherein the titania nanotubes have a band gap of between about 2.0 ev and about 2.2 ev.

4. The system of claim 2 wherein the electron mediator is palladium.

5. The system of claim 4 wherein the electrically conductive fluid is a dilute sulfuric acid solution or an imidazolium salt solution.

6. The system of claim 1 wherein the light source irradiates visible light.

7. The system of claim 1 wherein the carbon dioxide is converted to methanol via contact with the irradiated array of nanotubes.

8. The system of claim 1 further comprising a distillation unit, wherein the distillation unit distills the organic compound from the electrically conductive fluid.

9. The system of claim 8 further comprising a dehydration catalyst that converts at least a portion of the distilled organic compound to another organic compound.

10. A system for converting carbon dioxide to an organic compound, the system comprising:

an anode including an array of nanotubes;

a cathode including an electrically conductive material, the cathode cooperates with the anode to receive electrons from the anode;

an electrically conductive fluid, the anode and cathode being at least partially immersed in the electrically conductive fluid;

a light source that irradiates at least the anode;

a source of carbon dioxide; and

an inlet for delivering the carbon dioxide to the electrically conductive fluid whereat at least a portion of the carbon dioxide is converted to a different organic compound via contact with the anode, cathode, or both.

11. The system of claim 10 wherein the nanotubes are titania nanotubes.

12. The system of claim 11 wherein the titania nanotubes are carbon modified.

13. The system of claim 11 wherein the titania nanotubes have a band gap of between about 2.0 ev and about 2.2 ev.

14. The system of claim 10 wherein the nanotubes are titania nanotubes including nanoparticles of an electron mediator dispersed on a surface of the nanotubes.

15. The system of claim 14 wherein the electron mediator is palladium.

16. The system of claim 15 wherein the electrically conductive fluid is a dilute sulfuric acid solution or an imidazolium salt solution.

17. The system of claim 10 wherein the light source irradiates visible light.

18. The system of claim 10 wherein the carbon dioxide is converted to methanol.

19. The system of claim 10 wherein the electrically conductive material is a semiconductor material.

20. The system of claim 10 wherein the cathode defines a gas-diffusing p-type semiconductor including a titanium dioxide substrate.

21. The system of claim 10 further comprising a distillation unit, wherein the distillation unit distills the organic compound from the electrically conductive fluid.

22. The system of claim 21 further comprising a dehydration catalyst that converts at least a portion of the distilled organic compound to another organic compound.

23. The system of claim 10 wherein the system further includes a reference electrode to define a three electrode cell.

24. A method for converting carbon dioxide to an organic compound, the method comprising:

irradiating an array of nanotubes at least partially immersed in an electrically conductive fluid, the array of nanotubes including nanoparticles of an electron mediator that are dispersed on a surface of the nanotubes; and

delivering carbon dioxide to the electrically conductive fluid whereat at least a portion of the carbon dioxide is converted to a different organic compound via contact with the irradiated array of nanotubes.

25. The method of claim 24 further comprising distilling the organic compound from the electrically conductive fluid.

26. The method of claim 25 further comprising converting at least a portion of the organic compound to another organic compound.

27. The method of claim 26 wherein distilling the organic compound from the electrically conductive fluid comprises distilling methanol from the electrically conducting, and wherein converting at least a portion of the organic compound to another organic compound comprises converting at least a portion of the methanol to dimethyl ether via contact with a dehydration catalyst.

28. The method of claim 24 wherein the nanotubes are titania nanotubes.

29. The method of claim 28 wherein the titanic nanotubes have a band gap of between about 2.0 ev and about 2.2 ev.

30. The method of claim 24 wherein irradiating an array of nanotubes at least partially immersed in an electrically conductive fluid comprises irradiating with visible light the array of nanotubes at least partially immersed in the electrically conductive fluid.

31. A method for converting carbon dioxide to an organic compound, the method comprising:

irradiating an anode including an array of nanotubes, the anode being at least partially immersed in an electrically conductive fluid;

supplying electrons from the irradiated anode to a cathode including an electrically conductive material, the cathode being at least partially immersed in the electrically conductive fluid; and

delivering carbon dioxide to the electrically conductive fluid whereat at least a portion of the carbon dioxide is converted to a different organic compound via contact with the anode, cathode, or both.

32. The method of claim 31 further comprising distilling the organic compound from the electrically conductive fluid.

33. The method of claim 32 further comprising converting at least a portion of the organic compound to another organic compound.

34. The method of claim 33 wherein distilling the organic compound from the electrically conductive fluid comprises distilling methanol from the electrically conducting, and wherein converting at least a portion of the organic compound to another organic compound comprises converting at least a portion of the methanol to dimethyl ether via contact with a dehydration catalyst.

35. The method of claim 31 wherein the nanotubes are titania nanotubes.

36. The method of claim 31 wherein the titania nanotubes have a band gap of between about 2.0 ev and about 2.2 ev.

37. The method of claim 31 wherein the nanotubes are titania nanotubes including nanoparticles of an electron mediator dispersed on a surface of the nanotubes.

38. The method of claim 31 wherein irradiating an anode including an array of nanotubes comprises irradiating with visible light the anode including an array of nanotubes.

39. The method of claim 31 wherein the electrically conductive material is a semiconductor material.

40. The method of claim 31 wherein the cathode defines a gas-diffusing p-type semiconductor including a titanium dioxide substrate.