Photoelectrochemical reaction system

Patent metadata

Field	Value
Publication number	US-2016362801-A1
Application number	US-201615247178-A
Country	US
Kind code	A1
Filing date	Aug 25, 2016
Priority date	Mar 24, 2014
Publication date	Dec 15, 2016
Grant date	—

Abstract

A photoelectrochemical reaction system of an embodiment includes a CO 2 conversion part and a CO 2 reduction part. The CO 2 conversion part converts carbon dioxide into at least one intermediate substance selected from the group consisting of a metal carbonate and a metal hydrogen carbonate by an aqueous solution containing a metal hydroxide, and generates a reaction solution containing the intermediate substance. The CO 2 reduction part includes a one-liquid reaction vessel where the reaction solution containing the intermediate substance is led in, an oxidation electrode and a reduction electrode immersed in the reaction solution, and a photoelectric conversion element electrically connected to the oxidation and reduction electrodes. H 2 O is oxidized in a vicinity of the oxidation electrode to generate O 2 , and the intermediate substance is reduced in a vicinity of the reduction electrode to generate a carbon compound.

First claim

What is claimed is:

1 . A photoelectrochemical reaction system, comprising:
a conversion part converting carbon dioxide into at least one intermediate substance selected from the group consisting of a metal carbonate and a metal hydrogen carbonate by an aqueous solution containing a metal hydroxide, and generating a reaction solution containing the intermediate substance; a transfer part transferring the reaction solution containing the intermediate substance; and a reduction part comprising: a one-liquid reaction vessel where the reaction solution is led in by the transfer part; an oxidation electrode immersed in the reaction solution to oxidize water; a reduction electrode immersed in the reaction solution to reduce the intermediate substance; and a photoelectric conversion element electrically connected to the oxidation electrode and the reduction electrode, and performing a charge separation by light energy.

2 . The system according to claim 1 , wherein the conversion part includes the aqueous solution containing a hydroxide of at least one metal selected from the group consisting of an alkaline metal and an alkaline earth metal as the metal hydroxide.

3 . The system according to claim 1 , wherein the reduction part includes a stack in which the oxidation electrode, the photoelectric conversion element, and the reduction electrode are integrated, and the stack is immersed in the reaction solution.

4 . The system according to claim 1 ,
wherein the reduction part generates oxygen and hydrogen ions by oxidizing water by the oxidation electrode, and generates a carbon compound by reducing the intermediate substance by the reduction electrode, and wherein a collection part collecting at least one of the oxygen and the gaseous carbon compound generated at the reduction part is provided in the system.

5 . The system according to claim 1 , further comprising:
a reflux part refluxing the reaction solution where an oxidation-reduction reaction is generated at the reduction part to the conversion part.

6 . The system according to claim 1 , further comprising:
a storage part temporary storing the reaction solution generated at the conversion part.

7 . The system according to claim 1 , further comprising:
an adjustment part adjusting at least one of a concentration and pH of the reaction solution which is led into the reduction part.

8 . The system according to claim 1 , further comprising:
an impurity removal part removing a impurity from at least one of gas containing carbon dioxide which is transferred to the conversion part, and the reaction solution.

9 . The system according to claim 1 , wherein the conversion part includes a reaction tank accommodating the aqueous solution containing the metal hydroxide, and a gas supply pipe injecting gas containing carbon dioxide into the aqueous solution accommodated in the reaction tank.

10 . The system according to claim 1 , wherein a plurality of the reduction parts are provided in the system, and the transfer part is connected to the plural reduction parts.

11 . The system according to claim 1 , wherein pH of the aqueous solution containing the metal hydroxide is 7 or more and 14 or less.

12 . The system according to claim 6 , wherein the conversion part operates at night, the reduction part does not operate at night, and the reaction solution generated at the conversion part at night is stored at the storage part.

13 . The system according to claim 4 , wherein a gaseous product generated by an oxidation-reduction reaction at the reduction part is collected at an upper space of the reaction vessel, and is then transferred to the collection part from the upper space via a product send-out pipe.

14 . The system according to claim 13 , wherein the reaction solution is led into the reaction vessel to be within a range of 50% to 90% relative to an internal capacity of the reaction vessel.

15 . The system according to claim 1 , further comprising:
a reflux part refluxing the reaction solution where an oxidation-reduction reaction is generated at the reduction part to the conversion part; and an adjustment part adjusting at least one of a concentration and pH of the reaction solution which is led into the reduction part, wherein the reaction vessel includes a reaction solution lead-in pipe connected to the transfer part, an adjustment solution lead-in pipe connected to the adjustment part, a reaction solution lead-out pipe connected to the reflux part, and a reaction solution discharge pipe discharging the reaction solution after reaction.

16 . The system according to claim 15 , wherein a lead-in of the reaction solution into the reaction vessel and a lead-out of the reaction solution out of the reaction vessel are performed continuously or discontinuously.

17 . The system according to claim 15 , wherein pH of the reaction solution in the reaction vessel is adjusted in a range of 10 to 14 by the reaction solution lead-in pipe, the adjustment solution lead-in pipe, the reaction solution lead-out pipe, and the reaction solution discharge pipe.

18 . The system according to claim 1 ,
wherein the oxidation electrode includes a first support substrate and oxidation catalyst layers formed at both surfaces of the first support substrate, and wherein the reduction electrode includes a second support substrate and reduction catalyst layers formed at both surfaces of the second support substrate.

19 . The system according to claim 3 , wherein the stack has a through hole formed in a stacking direction of the oxidation electrode, the photoelectric conversion element, and the reduction electrode.

20 . The system according to claim 10 , wherein the transfer part is connected to the plural reduction parts in parallel.

Assignees

• Toshiba Kk

Inventors

• Huang Chingchun
• Mikoshiba Satoshi
• Ono Akihiko
• Kitagawa Ryota
• Kudo Yuki
• Tamura Jun
• Tsutsumi Eishi

Classifications

• C25B1/06

  Chemistry & Metallurgy · mapped topic

• C25B9/06

  Chemistry & Metallurgy · mapped topic

• C25B1/003

  Chemistry & Metallurgy · mapped topic

• C25B3/04 Primary

  Chemistry & Metallurgy · mapped topic

• H10F77/48

  Back surface reflectors [BSR] · CPC title