Method for reducing carbon dioxide

Patent metadata

Field	Value
Publication number	US-9598779-B2
Application number	US-201514935370-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Jul 5, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

In a carbon dioxide reduction method according to the present disclose, used is a carbon dioxide reduction device comprising a cathode container in which a first electrolyte containing carbon dioxide is stored, an anode container in which a second electrolyte is stored, a solid electrolyte membrane, a condenser, a cathode electrode having a metal or a metal compound on the surface thereof, and anode electrode having a region formed of a nitride semiconductor layer in which a GaN layer and an Al x Ga 1-x N layer are stacked. The anode electrode is irradiated with light condensed by the condenser and having a wavelength of not more than 360 nanometers to reduce the carbon dioxide contained in the first electrolyte on the cathode electrode.

First claim

The invention claimed is:

1. A method for reducing carbon dioxide using a carbon dioxide reduction device, the method comprising:
(a) preparing the carbon dioxide reduction device comprising:
a cathode container;
an anode container;
a solid electrolyte membrane;
a condenser;
a cathode electrode; and
an anode electrode, wherein

the cathode electrode comprises a metal or a metal compound on a surface thereof;
the anode electrode comprises, on a surface thereof, a region formed of a nitride semiconductor layer in which a GaN layer and an Al x Ga 1-x N layer (0<x≦1) are stacked;
a first electrolyte is stored in the cathode container;
a second electrolyte is stored in the anode container;
the cathode electrode is in contact with the first electrolyte;
the anode electrode is in contact with the second electrolyte;
the solid electrolyte membrane is interposed between the cathode container and the anode container;
the first electrolyte contains carbon dioxide; and
the cathode electrode is electrically connected to the anode electrode without an external power supply; and
(b) irradiating the anode electrode with light condensed through the condenser and having a wavelength of not more than 360 nanometers to reduce the carbon dioxide contained in the first electrolyte on the cathode electrode.

2. The method according to claim 1 , wherein
in the step (b), the light with which the anode electrode is irradiated has a light intensity of not less than 5 mW/cm 2 .

3. The method according to claim 2 , wherein
the condenser is a condensing lens or a condensing mirror.

4. The method according to claim 1 , wherein
the value of x falls within the range of more than 0 and not more than 0.25.

5. The method according to claim 1 , wherein
the GaN layer is of n-type or n + -type.

6. The method according to claim 1 , wherein
at least a part of a surface of the Al x Ga 1-x N layer is covered with metal particles containing nickel or metal oxide particles containing nickel.

7. The method according to claim 1 , wherein
the metal disposed on the surface of the cathode electrode is indium, gold, or an alloy thereof.

8. The method according to claim 1 , wherein
the first electrolyte is a potassium hydrogen carbonate aqueous solution, a sodium hydrogen carbonate aqueous solution, a potassium chloride aqueous solution or a sodium chloride aqueous solution.

9. The method according to claim 1 , wherein
the second electrolyte is a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

10. The method according to claim 1 , wherein
the carbon dioxide reduction device is at room temperature and at atmospheric pressure in the step (b).

11. The method according to claim 1 , wherein
the light is sunlight or pseudo sunlight in the step (b).

12. The method according to claim 1 , wherein
formic acid or carbon monoxide is obtained in the step (b).

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Hashiba Hiroshi
• Deguchi Masahiro
• Yotsuhashi Satoshi
• Yamada Yuka

Classifications

• C25B3/04

  Chemistry & Metallurgy · mapped topic

• C07C53/02

  Formic acid · CPC title

• C25B9/08

  Chemistry & Metallurgy · mapped topic

• C01B31/18

  Chemistry & Metallurgy · mapped topic

• C07C51/00

  Preparation of carboxylic acids or their salts, halides or anhydrides (of acids by hydrolysis of oils, fats or waxes C11C) · CPC title