Photoelectrochemical Cell

• US 20080286643A1
• Filed: 05/13/2005
• Published: 11/20/2008
• Est. Priority Date: 05/31/2004
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Iwasaki, Yasukazu
• Granted Patent: US 8,791,354 B2
• Time in Patent Office: Days
• US Class Current: 429/111
• CPC Class Codes: B01D 2255/802 Photocatalytic
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/326 in electrochemical cells
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/864 Removing carbon monoxide or hydrocarbons
• CPC Class Codes: C25B 1/55 Photoelectrolysis
• CPC Class Codes: H01G 9/2013 the electrolyte comprising ionic liquids, e.g. alkyl imidazolium iodide
• CPC Class Codes: H01G 9/2018 characterised by the ionic charge transport species, e.g. redox shuttles
• CPC Class Codes: H01M 14/005 Photoelectrochemical storage cells light sensitive devices H01G9/20, semiconductors sensitive to light H01L31/00
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A photoelectrochemical cell (1) includes an electrolyte container (3) containing an ionic liquid (2), and a partitioning membrane (4) dividing an interior of the electrolyte container (3) into two being a CO₂ capturing chamber (7) and a CO₂ releasing chamber (8), having side walls opposing each other, with the partitioning membrane (4) in between, either as a carbon electrode (5) and the other as a photoelectrode (6). A redox mediator (B) has different bonding forces to carbon dioxide, as it appears as an oxidant B_ox and a reductant B_red, of which that one which has a greater bonding force serves as an intermediary chemical species carrying carbon dioxide to one of the paired electrodes (5, 6). Over the CO₂ releasing chamber (10), an upper wall portion (10) is formed, which has a CO₂ take-out port (10A) formed therein, for making use of oxidation and reduction of the redox mediator to achieve separation and concentration of carbon dioxide, converting photo energy of sunlight into electric power.

Claims

1. A photoelectrochemical cell in which at least one pair of mutually spaced electrodes are disposed in electrolyte containing a redox mediator, at least one electrode of the electrodes being an optical electrode having a photocatalyst configured for light irradiation thereon to produce an excited electron, and which is adapted by the optical electrode to perform oxidation or reduction of the redox mediator in electrolyte for conversion of light energy to electric power, wherein

the redox mediator is a mediation chemical species such that an oxidant and a reductant exhibit different bonding forces to carbon dioxide, the one exhibiting the higher bonding force carrying carbon dioxide to one of the pair of electrodes.

2. The photoelectrochemical cell as claimed in claim 1, wherein electrolyte has a solvent comprising a nonaqueous solvent.

3. The photoelectrochemical cell as claimed in claim 1, wherein electrolyte has a solvent comprising an ionic liquid.

4. The photoelectrochemical cell as claimed in claim 1, wherein a gas containing carbon dioxide is supplied in electrolyte at an electrode side where the mediation chemical species is recovered.

5. The photoelectrochemical cell as claimed in claim 1, further characterized by a partitioning membrane for separation between electrolyte at an electrode side where the mediation chemical species is recovered and electrolyte at an electrode side where the mediation chemical species transfers carbon dioxide, and for ion conduction therebetween.

6. The photoelectrochemical cell as claimed in claim 1, wherein one electrode adapted for recovery of the mediation chemical species has a porous structure configured for prevention of permeation of liquid and for permeation of gas.

7. The photoelectrochemical cell as claimed in claim 6, wherein the electrode adapted for recovery of the mediation chemical species is configured to contact electrolyte at one principal side thereof and to contact a gas containing carbon dioxide at the other principal side thereof.

8. The photoelectrochemical cell as claimed in claim 1, wherein the optical electrode is configured to shield ultraviolet rays striking to the photocatalyst.

9. The photoelectrochemical cell as claimed in claim 1, wherein the optical electrode comprises a photocatalyst film contacting electrolyte, and a transparent collector film provided with the photocatalyst film, the photocatalyst film or the collector film having a light shielding effect.

10. The photoelectrochemical cell as claimed in claim 1, wherein the optical electrode is photosensitized with a light-absorbing dye.

11. The photoelectrochemical cell as claimed in claim 1, wherein a solar cell is electrically connected in series to the pair of electrodes.

12. The photoelectrochemical cell as claimed in claim 1, characterized by a solar cell laminated on the photoelectrochemical cell.