Panasonic Intellectual Property Management Co., Ltd.

Hiroshi Hashiba

Yuka Yamada

Masahiro Deguchi

Satoshi Yotsuhashi

Takeyuki Sekimoto

Reiko Taniguchi

Kazuhiro Ohkawa

Shuichi Shinagawa

Keiichi Noda

A method for reducing carbon dioxide is provided. In the present method, used is an anode electrode comprises a stacked structure of a photoelectric conversion layer, a metal layer, and an InGaN layer (where 0&#x3c;x&#x2264;1). The InGaN layer is of i-type or n-type. The metal layer is interposed between the photoelectric conversion layer and the InGaN layer. When irradiating the anode electrode with light, a first light part included in the light is absorbed by the InGaN layer and a second light part included in the light travels through the InGaN layer. The second light part is absorbed by the photoelectric conversion layer to generate electric power in the photoelectric conversion layer. The second light part has a longer wavelength than the first light part. The carbon dioxide contained in the first electrolyte solution is reduced on the cathode electrode.

Method for reducing carbon dioxide and device used therefor

The present invention provides a method for splitting water. In the present method, first, prepared is a water splitting device comprising: cathode and anode containers in which first and second electrolyte solutions are stored respectively; a proton exchange membrane disposed therebetween; a cathode electrode in contact with the first electrolyte solution and comprises a metal or metal compound; and an anode electrode in contact with the second electrolyte solution and comprises a nitride semiconductor layer. Then, the anode electrode is irradiated with light to split water contained in the first electrolyte solution. The anode electrode comprises a cobalt oxide layer formed of CoOas a main component on a surface of the nitride semiconductor layer; the surface of the nitride semiconductor layer being in contact with the second electrolyte solution. The cathode electrode is electrically connected to the anode electrode without an external power supply.

Water splitting method

The carbon dioxide reducing method using light includes: (a) preparing a carbon dioxide reducing cell including: a cathode chamber that holds first electrolytic solution containing carbon dioxide; an anode chamber that holds second electrolytic solution; a proton exchange membrane inserted between the cathode and anode chambers; a cathode set inside the cathode chamber to contact the first electrolytic solution, and the cathode having copper, gold, silver, indium, etc. on the cathode; and an anode set inside the anode chamber to contact the second electrolytic solution, the anode having first semiconductor layer constituted by nitride semiconductor including AlGaN layer wherein 0&#x2266;x&#x2266;0.25, an n-type GaN layer, and second semiconductor layer constituted by semiconductor having pn junction structure and electrically connected to the first semiconductor layer through p-type semiconductor layer, further to the cathode through no external power source; and (b) irradiating the anode with light to reduce carbon dioxide on the cathode.

Carbon dioxide reducing method, carbon dioxide reducing cell, and carbon dioxide reducing apparatus

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 AlGaN 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.

Method for reducing carbon dioxide

Disclosed is an anode electrode including a nitride semiconductor layer. This nitride semiconductor layer includes an AlGaN layer (0&#x3c;x&#x2266;0.25), an AlGaN layer (0&#x2266;y&#x2266;x), and a GaN layer. The AlGaN layer is interposed between the AlGaN layer and the GaN layer. The value of x is fixed in the thickness direction of the AlGaN layer. The value of y decreases from the interface with the AlGaN layer f toward the interface with the GaN layer. The AlGaN layer is irradiated with light having a wavelength of 360 nm or less so as to reduce carbon dioxide.

Photoelectrode used for carbon dioxide reduction and method for reducing carbon dioxide using the photoelectrode

In a method for generating formic acid by reducing carbon dioxide, a formic acid generation apparatus is prepared. The apparatus includes: a cathode container for storing a first electrolyte solution containing carbon dioxide; an anode container for storing a second electrolyte solution; a solid electrolyte membrane sandwiched between the cathode and anode containers; a cathode electrode provided in the cathode container in contact with the first electrolyte solution, the cathode electrode having a gallium oxide region on a surface thereof; an anode electrode provided in the anode container in contact with the second electrolyte solution; and an external power supply for applying a negative voltage and a positive voltage to the cathode electrode and the anode electrode, respectively. A negative voltage and a positive voltage are applied to the cathode electrode and the anode electrode, respectively, using the external power supply to generate formic acid on the cathode electrode.

Formic acid generation apparatus and method

Disclosed is a method for producing an alcohol using a device for reducing carbon dioxide by light energy. In this device, a cathode electrode includes copper or a copper compound, and an anode electrode includes a region including a nitride semiconductor layer in which an AlGaN layer (0&#x3c;x&#x2266;1) and a GaN layer are laminated. A first electrolytic solution consisting of an aqueous potassium chloride solution (aqueous KCl solution) is contained in a cathode chamber in which the cathode electrode is placed. A second electrolytic solution including an aqueous sodium hydroxide solution (aqueous NaOH solution) is contained in an anode chamber in which the anode electrode is placed.

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Osaka, Japan

Hiroshi Hashiba