Photoelectrochemical reaction system

Abstract

A photoelectrochemical reaction system of an embodiment includes a CO2 conversion part and a CO2 reduction part. The CO2 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 CO2 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. H2O is oxidized in a vicinity of the oxidation electrode to generate O2, and the intermediate substance is reduced in a vicinity of the reduction electrode to generate a carbon compound.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of prior International Application No. PCT / JP2015 / 001205 filed on Mar. 5, 2015, which is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-060061 filed on Mar. 24, 2014; the entire contents of all of which are incorporated herein by reference.TECHNICAL FIELD[0002]Embodiments disclosed herein generally relate to a photoelectrochemical reaction system.BACKGROUND ART[0003]From viewpoints of energy problems and environmental problems, a technology effectively reducing CO2 by light energy such as plants has been required. The plants use a system which is excited in two stages by the light energy called as a Z scheme. Namely, the plants obtain electrons from water (H2O) by the light energy, and synthesize cellulose and saccharide by reducing carbon dioxide (CO2) using the electrons. As a device performing an artificial photosynthesis, development of a photoelectrochemical ...

AI Technical Summary

Benefits of technology

The patent text describes a photoelectrochemical reaction system that can reduce CO2 by light energy. The system includes a photoelectric conversion element, a photoelectrochemical reactor, and a photoelectrochemical module. The technical effects of the patent text include improving the efficiency of CO2 reduction, developing a cost-effective and compact device, and considering the transport properties and efficiency of CO2 from the device discharging CO2 to the electrolytic device. The patent text also describes the configurations and operation of the photoelectrochemical reaction system.

Problems solved by technology

When water is used as an electrolytic solution, a dissolved concentration of CO2 is low, and therefore, it is impossible to increase a decomposition efficiency of CO2.

In a conventional photoelectrochemical reactor, the amine solution used as the CO2 absorbent has low chemical stability, and it is gradually oxidized under a natural state.

However, this incurs complication of a cell structure, and therefore, a device cost increases, and the device is easy to be further large-sized.

The ionic liquid is chemically stable, but it is expensive in itself, and therefore, the device cost increases.

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