Method and apparatus for preparing reduction product of carbon dioxide by electrochemically reducing carbon dioxide

Patent metadata

Field	Value
Publication number	US-2018202056-A1
Application number	US-201615744327-A
Country	US
Kind code	A1
Filing date	Jul 14, 2016
Priority date	Jul 14, 2015
Publication date	Jul 19, 2018
Grant date	—

Abstract

The present invention relates to a method and an apparatus of preparing a reduction product of carbon dioxide by electrochemically reducing carbon dioxide.
The present invention can prepare, in an energy-efficient manner, a reduction product of high-concentration carbon dioxide with high Faraday efficiency as in a liquid reduction reaction by producing the reduction product of carbon dioxide by supplying water or an electrolytic solution to an anode region; supplying humidified carbon dioxide gas having a second temperature higher than a first temperature to a cathode region within an electrochemical cell having the first temperature so as to supply the carbon dioxide gas which has been humidified to be in a condition where the relative humidity is greater than 100%, while applying a voltage between the anode region and the cathode region so as to generate hydrogen ions (H + ) in the anode region; and transporting the hydrogen ions to the cathode region through the electrolyte membrane, thereby electrochemically reducing the carbon dioxide gas.

First claim

1 . A method of preparing a reduction product of carbon dioxide (CO 2 ) by electrochemically reducing carbon dioxide within an electrochemical cell, which comprises an anode, a cathode, and an electrolyte membrane which is disposed between the anode and the cathode to separate the anode region and the cathode region:
(1) supplying water or an electrolytic solution to the anode region; (2) supplying a carbon dioxide gas which has been humidified in a condition where the relative humidity exceeds 100% to the cathode region within the electrochemical cell; and (3) applying a voltage between the anode region and the cathode region to generate hydrogen ions (H + ) in the anode region, wherein the hydrogen ions move through the electrolyte membrane to the cathode region and then electrochemically reduce the carbon dioxide gas so as to produce a reduction product of carbon dioxide.

2 . The method of claim 1 , wherein, upon applying a voltage in step (3), the moisture in which carbon dioxide is dissolved is condensed as the relative humidity within the cathode region exceeds 100% and forms a water film on the cathode surface, and the reduction product is produced from the carbon dioxide dissolved in the water film as a reactant by electrochemical reduction.

3 . The method of claim 1 , wherein the electrochemical cell comprises a membrane-electrode assembly having an anode catalyst layer and a cathode catalyst layer formed on each surface of the electrolyte membrane, respectively, and a gas diffusion layer of supplying the humidified carbon dioxide to the catalyst layer, which is placed in the cathode side of the membrane-electrode assembly.

4 . The method of claim 1 , wherein the reduction product of the carbon dioxide is formic acid, formaldehyde, formate, acetaldehyde, acetate, acetic acid, acetone, 1-butanol, 2-butanol, 2-butanone, ethanol, isopropanol, lactate, lactic acid, methanol, 1-propanal, 1-propanol, propionic acid, or a mixture thereof.

5 . The method of claim 1 , wherein a first temperature of the electrochemical cell is in the range of 10° C. to 25° C.

6 . The method of claim 1 , wherein a second temperature of the humidified carbon dioxide gas is in the range of 30° C. to 100° C.

7 . The method of claim 1 , wherein the relative humidity in step (2) is in the range of 150% to 2,000%.

8 . The method of claim 1 , wherein the reduction product of the carbon dioxide in step (3) is dissolved in the water derived from the humidified carbon dioxide gas and water which has undergone a crossover from the anode region, and produced in the form of an aqueous solution.

9 . The method of claim 1 , wherein the reduction product of the carbon dioxide produced in step (3) has a concentration of 1% (w/v) to 20% (w/v).

10 . The method of claim 1 , wherein the reduction product of the carbon dioxide in step (3) is produced with a Faradaic efficiency of 80% or higher.

11 . The method of claim 1 , wherein the cathode is selected from the group consisting of Sn, a Sn alloy, Al, Au, Ag, C, Cd, Co, Cr, Cu, a Cu alloy, Ga, Hg, In, Mo, Nb, Ni, NiCo 2 O 4 , a Ni alloy, a Ni—Fe alloy, Pb, Rh, Ti, V, W, Zn, Elgiloy®, nichrome, austenitic steel, duplex steel, ferrite steel, martensitic steel, stainless steel, degenerately-doped p-Si, degenerately doped p-Si:As, degenerately-doped p-Si:B, degenerately-doped n-Si, degenerately-doped n-Si:As, degenerately-doped n-Si:B, and mixtures thereof.

12 . The method of claim 11 , wherein the Sn alloy as the cathode is a Sn—Pb alloy.

13 . The method of claim 1 , wherein the electrolytic solution is an aqueous solution comprising an electrolyte of KHCO 3 , K 2 CO 3 , KOH, KCl, KClO 4 , K 2 SiO 3 , Na 2 SO 4 , NaNO 3 , NaCl, NaF, NaClO 4 , CaCl 2 , guanidinium cations, H + ions, alkali metal cations, ammonium cations, alkylammonium cations, halide ions, alkylamines, borates, carbonates, guanidinium derivatives, nitrites, nitrates, phosphates, polyphosphates, perchlorates, silicates, sulfates, tetraalkylammonium salts, or a mixture thereof.

14 . An apparatus of preparing a reduction product of carbon dioxide (CO 2 ) by electrochemically reducing carbon dioxide, comprising:
an electrochemical cell, which comprises an anode; a cathode; and an electrolyte membrane which is disposed between the anode and the cathode to separate the anode region and the cathode region; an inlet of supplying water or an electrolytic solution to the anode region; and an inlet of supplying humidified carbon dioxide to the cathode region; an energy supply source, which is operably linked to the anode and the cathode, and applies a voltage between the anode and the cathode to reduce the carbon dioxide in the cathode to a reduction product of the carbon dioxide; and a humidifier or atomizer, which is linked to the inlet for supplying humidified carbon dioxide to the cathode region and supplies humidified carbon dioxide to the cathode region, wherein water or an electrolytic solution is supplied to the anode region; a carbon dioxide gas which has been humidified in a condition where the relative humidity exceeds 100% is supplied to the cathode region within the electrochemical cell; and a voltage is applied between the anode and the cathode to generate hydrogen ions (H + ) in the anode region, the hydrogen ions are transported to the cathode region through the electrolyte membrane, and electrochemically reduce the carbon dioxide gas and a reduction product of carbon dioxide is produced.

15 . The apparatus of claim 14 , wherein, upon applying a voltage, the moisture in which carbon dioxide is dissolved is condensed as the relative humidity within the cathode region exceeds 100% and forms a water film on the cathode surface, and the reduction product is produced from the carbon dioxide dissolved in the water film as a reactant by electrochemical reduction.

16 . The apparatus of claim 14 , wherein the electrochemical cell comprises a membrane-electrode assembly having an anode catalyst layer and a cathode catalyst layer formed on each surface of the electrolyte membrane, respectively, wherein a gas diffusion layer of supplying the humidified carbon dioxide to the catalyst layer, which is placed in the cathode side of the membrane-electrode assembly.

17 . The method of claim 1 , wherein the electrochemical cell has a first temperature, and the supply of the carbon dioxide gas which has been humidified in a condition where the relative humidity exceeds 100% in step (2) is achieved by providing a humidified carbon dioxide gas having a second temperature higher than the first temperature to the cathode region within the electrochemical cell.

18 . The apparatus of claim 14 , wherein the electrochemical cell has a first temperature, and the supply of the carbon dioxide gas which has been humidified in a condition where the relative humidity exceeds 100% is achieved by providing a humidified carbon dioxide gas having a second temperature higher than the first temperature to the cathode region within the electrochemical cell.

Assignees

• Korea Inst Energy Res

Inventors

• Park Ki Tae
• Jeong Soon Kwan
• Kim Hak Joo
• Kang Seong Pil
• Youn Min Hye

Classifications

• C07C53/10

  Salts thereof · CPC title

• C07C53/06

  Salts thereof · CPC title

• C07C51/15

  by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis · CPC title

• C01B32/50

  Carbon dioxide · CPC title

• C01B32/40

  Carbon monoxide · CPC title