Means for reducing carbon dioxide to provide a product

• US 4,609,451 A
• Filed: 03/18/1985
• Issued: 09/02/1986
• Est. Priority Date: 03/27/1984
• Status: Expired due to Fees

• Current Assignee: Texaco Incorporated (Chevron Corp.)
• Original Assignee: Texaco Incorporated (Chevron Corp.)
• Inventors: Sammells, Anthony F., Pa Ang, Peter G.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Chapman, Terryence
• Application Number:
  US06/713,212
• Time in Patent Office: 533 Days
• Field of Search: 204/72, 204/73, 204/75-77, 204/158 R, 204/258, 204/265, 204/266, 204/282, 204/283, 204/295, 204/296, 204/59 R, 429/111
• US Class Current: 204/265
• CPC Class Codes: B01D 61/00 Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor separation of gases or vapours by diffusion B01D53/22
• CPC Class Codes: B01D 69/141 Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
• CPC Class Codes: C25B 1/55 Photoelectrolysis
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Abstract

A process and apparatus for reducing carbon dioxide to at least one useful product includes two redox couple electrolyte solutions separated by a first membrane having photosensitizers. The carbon dioxide to be reduced is provided to a second membrane whch is contiguous to one of the redox couple electrolyte solutions. The second membrane has photosensitizers and a catalyst. Water provides hydrogen ions, which participate in the reduction of the carbon dioxide, via a separator. In operation both membranes are illuminated and produce excited photosensitizers which cause electron transfer from a first redox solution to a second redox solution and thence to the carbon dioxide in the second membrane thereby, in cooperation with the hydrogen ions, reducing at least some of the carbon dioxide at a surface of the second membrane to provide at least one product.

Claims

1. Apparatus for reducing carbon dioxide to provide at least one product comprises:

means for containing a first redox coupled electrolyte solution,

means for containing a second redox coupled electrolyte solution,

first means responsive to illumination for transferring electrons from the first electrolyte solution to the second electrolyte solution,

means for containing water,

means for providing carbon dioxide,

means for providing hydrogen ions from the water, and

reduction means connected to the carbon dioxide means and responsive to illumination for reducing the carbon dioxide in the presence of transferred electrons from the second redox coupled electrolyte solution and hydrogen ions.

2. Apparatus as described in claim 1 in which the reduction means includes:

semiconductor means responsive to illumination for transferring electrons from an electrolyte solution, and

hydrophobic means adjacent to the semiconductor means and having a catalyst impregnated surface and passageways for the carbon dioxide for permitting a substantial portion of the carbon dioxide to migrate to and through the catalyst impregnated surface to a reduction site and not permeable to electrolyte.

3. Apparatus as described in claim 2 in which the semiconductor means utilizes semiconductive material selected from a group of photosensitizers consisting of p-InP, p-WSe₂, p-GaAs, p-CdTe, n-WSe₂, n-CdSe, Ru(bipy)₃ Cl₂ and phthalocyanines.

4. Apparatus as described in claim 3 in which the catalyst is impregnated in the surface of the hydrophobic means and is selected from a group of catalysts consisting of dichalcogenides (Ni, Co, Mo, W), SrTiO₃, NADPH, metal coatings (Pb, In), amalgams (Ni, Zn), chrysene, ethyl acrylate, phthalocyanines (Ni, Co), porphyrins and methyl viologen.

5. Apparatus as described in claim 4 in which a biasing voltage is provided across the first electrolyte solution and the water in a manner so that the water is anodically biased relative to the first electrolyte solution.

6. Membrane means comprising:

semiconductor means responsive to illumination and for transferring electrons from an electrolyte solution, and

electrolyte impermeable hydrophobic means adjacent to the semiconductor means and having a catalyst impregnated surface and passageways for receiving carbon dioxide and for permitting a substantial portion of the carbon dioxide to migrate to and through the catalyst impregnated surface.

7. Membrane means as described in claim 6 in which the semiconductor means utilizes semiconductive material selected from a group of photosensitizers consisting of p-InP, p-WSe₂, p-GaAs, p-CdTe, n-WSe₂, n-CdSe, Ru(bipy)₃ Cl₂ and phthalocyanines.

8. Membrane means as described in claim 7 in which the catalyst is impregnated in the surface of the hydrophobic means and is selected from a group of catalysts consisting of dichalcogenides (Ni, Co, Mo, W), SrTiO₃, NADPH, metal coatings (Pb, In), amalgams (Ni, Zn), chrysene, ethyl acrylate, phthalocyanines (Ni, CO), porphyrins and methyl viologen.